Tristie Campbell-Gregory de Lœngbærrow Junior ran out of the TARDIS as soon as it materialised disguised as a ramshackle and sun-weathered shack. His mother rushed out after him.

“Sweetheart, be careful,” Trudi said to her ten year old. “You never can tell. Your dad MEANT to bring us to New Mexico in the early twenty-first century, but it could be Egypt at the time of the plagues or the desert world of Dephisa X.”

“It’s New Mexico,” Tristie senior assured them as he closed the TARDIS door and shouldered the overnight bag that leant veracity to the idea of them as ordinary visitors to the small town they had chosen to visit. “Uncle Davie tuned up the navigation control. Getting lost in space and time shouldn’t happen, now.”

Tristie harboured a small regret about that. Getting lost and finding new places and people by accident was what having a TARDIS was all about. He had grown up on stories about his great-great grandfather, The Doctor, and the adventures he had in a TARDIS he could hardly ever control. Being able to pinpoint an exact time and place took the fun out of it a little.

But The Doctor never had those adventures with his wife and ten year old son aboard his TARDIS. Being sure of not running into Daleks, Cybermen and other deadly foes was a good thing, on balance.

“So… can you hear it?” he asked them. Trudi and Junior both stood still and listened. It was early morning. There was no traffic on the road, yet. There weren’t very many natural sounds. High above an eagle soared, looking for prey in the dry, scrubby territory. If he concentrated, Tristie could hear the wind in its feathers. He could hear rodents and snakes scurrying for cover as it searched.

He could, if he tried even harder, hear insects in the grass.

What he couldn’t hear was the thing that brought them here, the thing that Trudi had read about and insisted that they should follow up.

“I hear it,” Tristie Junior said.

“So do I,” Trudi added.

“I don’t,” Tristie admitted. “I thought I would. I have better hearing than ordinary humans, and I am telepathic. I thought I would be able to hear it.”

He turned slowly, looking across the flat wasteland to the line of grey mountains that bounded the territory. The TARDIS database had told him these were a subrange of the Rocky Mountains called the Sangre de Cristo Mountains – the Blood of Christ – named by devout Christian settlers who noted a distinctive red hue reflected off the peaks at sunset and interpreted it as a sign from God.

Turning full circle, he saw the outskirts of the town. Again, the database told him that it had a population of less than four thousand and an economy based largely on tourism. A large, friendly sign using a font loosely based on native art confirmed those facts.

“Welcome to Taos, New Mexico.”

“Nice to be welcomed,” he said. “Let’s go and find somewhere to get breakfast.”

The town was starting to wake up. The first lorry and a scattering of cars passed them as they walked through the mainly residential outskirts and came to the commercial centre. They noticed all the hallmarks of an American ‘small town’. There were no skyscrapers. Few of the buildings were over two storeys. The dominant architectural colour was a reddish-beige sympathetic to the traditional adobe buildings that were indigenous to the area. The database had images of a preserved adobe complex called Taos Pueblo nearby where people still lived and worked at traditional crafts. They would probably visit that in the coming days. Trudi liked traditional crafts. But for now somewhere that did a good traditional breakfast would do just fine.

They found it near the plaza in the Downtown Historic District. It was a small café with Native American murals on the outside gable walls and on the inside as well. They found a table by the window and enjoyed orange juice, omelettes and fried tomatoes with hash browns followed by a huge plate of pancakes loaded with fresh fruit. Tristie Junior especially appreciated those and had seconds while his parents enjoyed a pot of coffee.

“So… we came all the way to New Mexico to check out the infamous Taos Hum and YOU can’t hear it?” Trudi remarked.

“Apparently that’s not unusual,” Tristie answered. “The population is more or less divided between those who can hear it and those who can’t.”

“But it is strange that you can’t. I could, and so could Tristie Junior. And he’s got your Time Lord genes, so you SHOULD be able to hear it just like him.”

“According to the Congressional investigation done in 1997 there was no obvious genetic connection between hearers. The reason some people hear it and others don’t is as big a mystery as why there is a Hum in the first place.”

“They didn’t find the cause?”

“Possibly military,” Tristie answered with a wry smile.

“Possibly military?” Trudi echoed. “That’s the best they can come up with from a ‘Congressional Investigation’? I’m not sure what that is exactly, but it sounds like an expensive waste of time if that’s their conclusion.”

“I agree,” Tristie told her. “I think there’s a challenge here. I have to find something better than that for an answer. For the sake of science and family honour, I definitely have to look into it.”

“I knew you would.” Trudi grinned and poured herself another cup of coffee. It HAD been entirely her idea to come here to find out if the Taos Hum was real. Tristie had been dubious. He put it down to urban myth, to conspiracy theories, UFO believers, and most likely, the wind vibrating telephone wires. But he had indulged her whim and, as she fully expected, he had found his own enthusiasm.

As the waitress came to their table with a fresh coffee pot and a third stack of pancakes and strawberries for Tristie Junior a man came into the café. The waitress put down the coffee pot and went to speak to him. They talked in low voices, but Tristie, though he couldn’t hear the mysterious hum, could certainly pick up the conversation. He noticed the sympathetic way the waitress touched the man on the shoulder and offered him a cup of coffee.

“No, thanks, Jenny,” he answered. “I just hoped you’d hand out some of these flyers. I’ve got… more places to go.”

He gave her a handful of pages and turned to leave. As he did so, he noticed Tristie and his family at their table.

“You’re strangers here?” he asked.

“Just… visiting for a few days,” Tristie answered.

“You should get out while you can. Take your family and get away from here. This town isn’t safe any more for good people.”

“Jim, don’t,” Jenny the waitress said to him. “They’re nothing to do with this. Let them be.”

“You should go,” Jim repeated in a broken voice, “You’re a nice looking family. Don’t take the risk.”

With that he left the café. Tristie watched him go down the road to the gas station where he left more flyers. He turned and saw Trudi reading one of them. He saw that the two sides of the large sheet were covered with images of people along with their names and ages and dates when they went missing – all within the last four weeks.

“There must be fifty of them,” he commented. In his mind he was calculating the percentage of the population of four thousand that was.

It was one point two five.

“There might be nearer twice as many as that,” Jenny the waitress said. “Those are people with relatives who reported them missing. But we have homeless people in Taos, people who live alone… people who might not be missed.”

“Jim has somebody missing?” One point two five was a small number, but not if it was personal. Not if the ‘one’ was a loved one.

“His daughter. She’s eighteen. She used to work here with me, but it was only until she raised college money. That girl was going to grow right out of this little town.”

“Was?”

“She was one of the first, nearly a month ago. Jim hasn’t stopped looking. He started printing off these fliers. They used to be smaller, and all on one side of the paper.”

“The police don’t know anything?” Trudi asked.

“They’ve done their best. But they don’t have the resources. They….” Jenny sighed deeply. “I heard you talking before… about the Congressional Investigation. All the time and money spent on trying to find out about a noise. But they can’t investigate why Judy Brennan left her bed in the middle of the night and hasn’t been seen again.”

She sighed again.

“I’m sorry. You’re visitors to these parts. You shouldn’t be troubled by our problems. Besides… we need the tourism. We can’t go scaring folks like you off.”

She laughed as she said that, trying to make light of the matter, but the underlying sadness still showed on her face.

“It takes more than this to scare us off,” Tristie assured her. “Point us to a good hotel and we’ll freshen up and go see the sites.”

Jenny the waitress did just that. Tristie paid the bill and tipped her generously, promising to drop by again for pancakes. Then they walked across the plaza to the recommended hotel and booked in.

“Are the missing people connected to the Taos Hum?” Trudi asked as she dried her hair after a refreshing shower. The en-suite bathroom was currently occupied by Tristie Junior who was singing Raindrops Keep Falling on my Head loudly but more or less in tune.

“I don’t see an obvious connection,” Tristie answered. “The Hum has been around for decades. These people only started going missing a few weeks ago.”

“Are they dead? Does this lovely town have a serial killer as well as a freaky mystery?”

“The fact that no bodies have turned up is a good sign, in my humble opinion. Jim Brennan isn’t as hopeful as that, though. I was ten feet from him in the café but I could feel his grief radiating off him. He can’t believe his daughter wouldn’t contact him if she was alive.”

“Poor man. Can we do anything to help?”

“I’m not sure what, but I’d like to try. Meanwhile, I’m going to put you and Junior on the tour bus to Taos Pueblo. It leaves from the plaza down there in half an hour. You go buy native arts and crafts and chat to the locals. See what they think. I’m going to walk back to the TARDIS and bring it here. I think I’m going to need the advanced technology to figure some things out.”

Trudi was in two minds. It looked as if Tristie wanted to solve the mystery – or mysteries as it seemed to be – on his own. She felt strongly that she ought to be helping him, sharing the burden.

But on the other hand, a living village full of native crafts….

“Do I have a credit limit?” she asked.

“No, but let’s have a size limit. I don’t want a repeat of our trip to the Andolexian Antique Fair, trying to get that cabinet in through the TARDIS doors. Only buy things that will fit on the coach back to town.”

Trudi grinned and accepted that limitation on her shopping. She kissed her husband fondly and called her son to join her.

Tristie looked out of the hotel window to watch them board the tourist coach waiting in the plaza. As it pulled away he noticed Jim Brennan walking slowly around, scanning the faces of everyone he passed, whether local residents or tourists. He was hoping to see his daughter, of course, but perhaps he also expected to see something in a face… guilt, complicity….

“I’ll do what I can,” Tristie said quietly. It wasn’t his problem. He was a visitor to this town, to this country, to this particular time, even. He could investigate the Taos Hum as a scientific curiosity and leave the missing people to the local authorities.

He could have done that if Jim Brennan hadn’t come into that café, if he hadn’t felt the man’s grief so very powerfully, if he hadn’t learnt his name or the name of his missing daughter.

But knowing those things he couldn’t walk away. If there was anything he could do with his superior intellect and his advanced technology, he would do it.

Trudi and Tristie Junior came back to the hotel in the early evening loaded down with ‘traditional native hand crafts’. The largest souvenir was a ‘traditional’ drum made of locally sourced wood covered in elaborate and colourful designs. Tristie Junior had decided that his bedroom in their Liverpool apartment wasn’t complete without it and had carried it back on the coach for himself.

Trudi had contented herself with a woven blanket, two carved wooden fruit bowls and enough bead jewellery for a whole flower power commune.

She had also collected information. The people on the coach were tourists who knew little of the local problems, but the café where she and Tristie Junior had ice creams and the numerous craft shops were run by Taos citizens and when prompted they would talk readily.

Tristie did his best not to dismiss what the people had to say, as reported by Trudi, as complete nonsense, but it was difficult.

“Sweetheart, I am sure there is nothing happening at the Los Alamos research facility that requires Human guinea pigs culled from the population.”

“It’s only a bit more than fifty miles away, and its where they made the Bomb in World War Two,” she pointed out.

“Yes, but now they do medical research, looking for cures for cancer and that sort of thing. When they need to test anything they ask for volunteers and run properly monitored clinical trials. I am quite sure they haven’t kidnapped anyone. As for Roswell, that is nearly three hundred miles from here, and in any case, the aliens who crashed there were idiots. They were the space equivalent of teenagers with a provisional driving licence and a sports car. Everyone knows that in my century.”

“It is what people think happened.”

“Yes, I know. Desperate people with no answers cling to all sorts of theories.”

“All the people who’ve gone missing are Hearers,” Trudi added. “That can’t just be coincidence.”

“All of them?” This time Tristie was interested. “Is that for certain? I looked at the official population census, but they don’t collect data on that sort of thing. I found out that the missing people are from both genders, from all age groups from a seventeen year old boy to a seventy-four year old retired librarian, that they come from all parts of the city, all social classes, all ethnic groups. There’s no common factor I can find. So how does anyone know that the Missing are all Hearers?”

“They know. It’s just something that you know if you live here. All the people who aren’t Hearers know that they won’t be taken. They feel safe. I don’t mean that they’re smug about it at all. They fear for their friends, they sympathise with the grieving families, but they know for sure they won’t be taken themselves.”

“Taken?” Tristie picked up on that particular word. “Is that what they think? That the missing people were ‘taken’ by somebody or something?”

“Yes. That’s the word they all use. Nobody believes that those people vanished by themselves.”

“Neither do I,” Tristie admitted. “But if Hearers are being targeted, then there’s something I should do before I do anything else.”

He left Trudi to sort out her souvenirs and went into a large cupboard that wasn’t in the hotel room earlier. A few minutes later he came out of his TARDIS again carrying two strips of dark green acetate with printed circuits creating a faintly glowing geometric pattern within the material. He fixed one of them to his son’s wrist and the other to his wife’s.

“I’m afraid green acetate isn’t trendy in any era,” he told her. “But if anything happens to either of you, it will send me a signal. I’ll know where you are.”

“Could you make these for all the Hearers?” Trudi asked.

“I could, but they’d think I was a loopy tin hat wearer with a crackpot idea. And besides, if they all had signals, how would I find you and Junior among them? I feel deeply for those people, but I feel most of all for you two. I have to protect you, first. Now… I’m still thinking. I haven’t given up, but this hotel has a very nice restaurant and even Time Lords with a whole town to save need to eat.”

He never stopped thinking about it. His mind went over all the variables he had programmed into the TARDIS database, all the long range scans on every frequency he could think of, all of which had come up blank.

Well, all but one. He had, at least, found a better answer to the Taos Hum than that very expensive Congressional Investigation had managed, though he wasn’t sure he could tell anyone. It would definitely fall into the ‘tin hat conspiracy’ category along with Roswell aliens and secret experiments at Los Alamos.

But at least he knew, and he planned to tell Trudi about it later. She would get a real kick out of it. But not until they had done something about the other, sadder mystery that surrounded this American town. Until then she really couldn’t fully appreciate it.

He tried not to let it spoil his dinner. There was entertainment, afterwards, a small band playing a blend of country-rock that was easy on the ear even if it wasn’t his personal choice of musical genre. Tristie Junior stayed awake and appreciated it with his parents, though it was a struggle towards the end and he didn’t resist the indignity of being put to bed by his father even though he was ten years old.

Tristie Senior let his mind rest as he settled down in the double bed next to Trudi. He fully intended to get back onto it in the morning. Trudi had mentioned a coach trip to the rather impressive Rio Grande Gorge Bridge. A picnic lunch and tea at a diner with views over the Gorge were included in the ticket. He planned to bring the TARDIS and meet up for lunch while running more scans from a different focal point.

But for now, he was ready to sleep and refresh his body and mind so that he could approach the problem again in the morning.

It wasn’t quite morning when he was shaken awake by his son.

“Dad, mum is acting strange,” the boy said.

Tristie looked around the room in the half light of pre-dawn. Trudi, wearing a very minimalist lace nightie was trying to open the door leading out onto the second floor landing.

At least, part of her was trying. Part of her was trying to pull back, as if she was resisting the urge. When Tristie caught her hand she clung to it desperately while still scrabbling at the latch with the other.

“She’s hypnotised,” Tristie confirmed as he pulled her away from the door and she tried to go back to it while still resisting with what was left of her free will.

“Mum….” Tristie Junior ran to his adjoining bedroom and returned with the native drum he had bought yesterday. He tapped out a rhythm on it. “Mum, listen to this instead of the other sound.”

Trudi blinked and slumped into Tristie’s arms. Her son kept on tapping the drum softly until she had gathered her senses.

“It’s the Hum. It’s changed,” she explained. “It’s… calling me. Something was calling me back… I think it was the TARDIS, the hum it makes all the time, but I wanted to go.”

“Junior’s drumming broke the sound,” Tristie guessed. “I taught him about sonic resonance last week. Great thinking.”

“I can still hear the Hum,” Trudi reported. “It’s still trying to make me want to go.”

“The Hum shouldn’t do that,” Tristie insisted. “It’s not dangerous to anyone.”

A noise outside brought him to the window. In the plaza below at least a dozen people wearing night clothes quite unsuitable for outdoors were walking in a determined but, at the same time, unconscious, manner. The sound had been one of them tripping over the pavement sign outside the general store advertising a promotion on canned goods. The faller picked himself up and carried on walking with a slight limp.

“Where are they all going?” Junior asked.

“I don’t know, but I’m going to find out. Trudi, sweetheart, if there was any other way… but….”

Trudi looked puzzled for a few seconds, then the penny dropped.

“You want me to….”

“Junior and I will be right behind you,” he promised. “You’ll be safe. But before you get mesmerised again, put on a pair of shoes and a coat. You don’t want to cut your feet and that nightie is for me to appreciate not the general public.”

She did that before Tristie Junior stopped drumming. The mesmeric influence came over her almost at once. Tristie opened the door and let her out. She walked to the end of the landing and down the stairs. Tristie turned back and ran to the TARDIS followed by his son carrying the drum along. Moments later they were following the tide of mesmerised townspeople as they made their way out through the suburbs to the scrubby New Mexico landscape beyond.

“Can they see us?” Junior asked.

“The TARDIS is in stealth mode, silent and invisible,” Tristie answered. “Even if it wasn’t, most of them would be oblivious. Except for those two.”

On the big wall mounted screen, two people were clearly not hypnotised. One was Jim Brennan who was trying to rouse Jenny the Waitress from her stupor. The other was a police officer trying to do the same for an older man.

“That’s his boss, police chief Nichols,” Tristie confirmed. “I recognise him from a couple of public statements he made about the disappearances. Now it looks like he's a victim, too. The sergeant there must have been on the early shift.”

“Everyone else only has us to look after them.”

“I’m looking after your mum, first. I got her into this. But I’ll do my best. “

The sun was up by the time the crowd had walked across nearly three miles of rough countryside. Tristie was glad Trudi was wearing shoes, but some of the others were going to be suffering from cut and bruised feet. Few of them were properly dressed for outdoors, either, having been summoned from their beds. There were two men who obviously slept naked. Tristie had pixilated them for Junior’s eyes, but he would have to find a couple of blankets later.

“What’s that up ahead?” Junior asked, pointing to an obvious anomaly in the middle distance.

Obvious to anyone looking on a TARDIS viewscreen, at least. From the ground the slight shimmer where a domed cloak at least a hundred metres high at the apogee and four hundred metres in circumference might not be so easy to see.

And it cut right across the path of the hypnotised walkers.

“It’s very clever,” Tristie answered. “The TARDIS didn’t detect it at all until we were this close. All my scans yesterday missed it.”

He looked at the environmental monitor. Even now the TARDIS couldn’t penetrate the cloak. It showed as a void on the topography.

It showed people vanishing from the monitor as they stepped through the invisible but penetrable wall.

Penetrable from the outside. He would lay any bets it was more difficult from the inside.

Trudi was one of the people on screen. Her wristband allowed him to identify her in the crowd, but he knew he would lose her as soon as she went through.

“The TARDIS won’t go through,” Tristie confirmed. “It won’t go into ‘nothing’. Even the vacuum of space is ‘something’, but it just doesn’t register anything inside that dome.”

“Then we have to go in with everyone else,” Junior answered.

“We? Not so sure about that.”

“It’s for mum,” Junior reminded him. “And all these other people.”

“It could be a vacuum in there, or a portal to another world millions of light years from home.”

“Could be an ice cream shop,” Junior answered. “It’s like that Shroginger’s Cat in the box thing.”

Tristie smiled softly. Few ordinary ten year olds had heard of Schrödinger’s Cat. Even if he couldn’t pronounce the name of the Austrian physicist and philosopher he had correctly identified a situation in which the equation applied.

“Don’t set your heart on ice cream,” Tristie said as he brought the TARDIS to ground a few yards from the invisible wall and went to fetch those blankets. Tristie Junior brought his drum with him as father and son stepped out and prepared to face just about anything together.

Tristie had considered several more possibilities, but an alien space ship of classic ‘flying saucer’ design wasn’t actually one of them. Under the dome – opaque white on the inside - the machine was awkwardly positioned with one rim buried in the sand. It had clearly crash landed with only enough power to put up the cloak and maintain life support.

Nor was he prepared for the ring of Taos citizens who circled the ship. They were all dressed for bed, but some of them had obviously left the comfort and safety of their homes some time ago.

Jim Brennan gave a cry of distress and ran to a young woman in a cotton nightdress. He tried to hug her, but she was unresponsive. Tristie wanted to keep an eye on Trudi as she and took her place in the ring, but the others were his responsibility, too. He left his son with his mother and went to see what he could do for Judy Brennan.

“She’s under some form of suspended animation,” he said after scanning her with his sonic screwdriver. “That’s what’s kept her and the earlier ones alive. They don’t need food or drink. This dome must have protected against the weather, too. She’s not sunburnt and no sign of hypothermia from being here at night.”

Jim Brennan wasn’t reassured.

“Who are you? How do you know these things… suspended animation… what does that mean? Are you one of the aliens from this… this… this abomination.”

“No, I’m from London,” Tristie answered truthfully. It was several generations since his family had been alien to Earth. “Just try to trust me. I know a few things.”

“Do you know how to wake her up?” Jim Brennan asked.

“No… at least… Yes.” He turned and called out to his son. “Junior, play that drum again, as loud as you can.”

“A drum? What use is that?”

“The aliens have used a sonic resonance – a sound – to put them all under their influence. The drum disrupts that. Wait a moment….”

He was right. As Tristie Junior tapped out his rhythm the people began to wake. The new arrivals recovered first. Trudi Brennan and those kept there the longest were slower, but it worked. She stirred and swooned into her father’s arms.

“What happened to me?” she asked, a question being asked all around by people who were waking to a reality containing sore feet and an alien spaceship.

“It doesn’t matter, now. You’re safe,” her father told her.

“Not quite,” Tristie concluded. He looked around. The dome was failing. The landscape beyond was visible, now. The ship in the middle was vibrating slightly.

“I see!” he exclaimed. “This ship is powered by noetics… by mind power. The aliens must have lost some of their own crew and didn’t have the power to take off again. So they used these people like… like batteries.”

Those within earshot didn’t like to hear that they had been ‘batteries’. There were angry murmurs and some of them started to move towards the ship.

“No!” Tristie called out urgently. No… get right away from it. I think they have enough power to take off. That’s why they pulled in so many new people tonight… to give them the last boost. And… when did you ever see a spaceship take off without some kind of heat disruption? Everyone get back… get right back. Quickly.”

His warning was picked up and repeated until everyone got the message. The ring expanded as they ran in every direction. Jim Brennan ran clinging to his daughter’s hand, the police sergeant and his Chief picked up an elderly woman who had fallen and carried her along. Tristie Junior ran with his mother.

When Tristie was on his own he faced the space ship again.

“I’m bearing in mind that nobody suffered any lasting harm,” he called out. “But you would have killed all of them in your take off. That goes against you all big time. You used those human beings and you were ready to discard them when you had what you wanted. I don’t like that. I’ve been raised to value life higher than that. But that means I have to value your lives, too. That’s why I’m giving you enough of my mind power to get you to the outer limits of this solar system. After that you figure out for yourselves how to get back to your own planet… and you STAY THERE. Earth is out of bounds to the likes of you. Now GO.”

He turned and ran to the much wider perimeter where Trudi and Junior hugged him fondly. The space ship powered up noisily and the ground shook as it extracted itself from the sand. There was heat on their faces, but not so much as there would have been closer to ground zero.

It was gone so fast even the most dedicated UFO spotter would have failed to get a photograph. Tristie turned to the police chief and his sergeant.

“Get on your radio and call up a couple of coaches to pick everyone up. Take them to your local hospital. There are some minor injuries… mostly cut feet, but they should all be able to go home to their families later.”

“What the hell am I going to put in my report about this?” the Chief asked, half wondering why he was taking advice from a civilian, and a British one at that.

“It’s up to you,” Tristie answered. “You could tell the whole truth and let Taos become the new Roswell, overrun with conspiracy fans taking photos of the patch of melted sand over there. It could be a big boost for the hotel and café owners and souvenir shops, but I imagine it would also be a real nuisance, and I think your town is nice enough with its native art and adobe architecture. If it was up to me I’d delete all those missing person reports and let the whole thing blow over.”

“I… might just do that,” the Chief decided. “The coaches are on the way. They’re bringing first aid kits and bottled water.”

“Good thinking. Well, I’m going to take my family back to town. You look after your people.”

“Take your family back….” The Chief was puzzled. There were no cars in sight, nothing but an old shack that he didn’t remember seeing before. He was even more puzzled when he saw the young British man with so much knowledge of alien space ships heading towards the same shack.

He was distracted by the appearance of the coaches in the middle distance and so missed the mysterious disappearance of the shack.

“We could have brought them all into the TARDIS,” Trudi pointed out as Tristie programmed their return to the hotel.

“Better not. One spaceship is enough for them to think about. Let the Chief and his sergeant look after them. We’ll just go back to bed catch up on some sleep. I’m afraid day trips to the Gorge are off today. The coach was requisitioned for the rescue. We’ll do that tomorrow.”

“Sounds good to me,” Trudi decided.

“One more thing before then.” Tristie smiled widely and reached for a switch. “I said there were two mysteries here. The aliens were using the Taos Hum to piggy back their hypnotic signal, but I also found out about the Hum itself.”

He flicked the switch and a beautiful music filled the air. It was like a cross between harp strings and Tibetan singing bowls.

“It’s beautiful,” Trudi enthused. “What is it?”

“It’s the Taos Hum when it isn’t blocked by hundreds of feet of rock and soil. The sound comes from another bunch of aliens that came to this planet tens of thousands of years ago. They’re called Crisialog, single celled beings made of crystal. Their one purpose in their simple lives is to make this music, but it is rarely heard as it ought to be.”

“What a shame. It is so beautiful. People in Taos think of the Hum as a bit of a nuisance. Some of them say it gives them headaches and ruined sleep. If they knew it was so lovely….”

“Yes, but they’ve had enough aliens to last a lifetime. I think we’ll leave them alone with the mystery. We know the truth, which is why we came in the first place. Mission accomplished.”