The gas smell grew stronger. David R. was already too weak from the gas to resist. He coughed; the cough became a chortle as the effect of the gas began to really hit him.

"More," Mr Tilley said, calmly. Justine turned the gas up a little higher. David couldn't stop chuckling. Within a few seconds, he was roaring out loud with giggly laughter. If his body hadn't been relaxed by the gas earlier, by now he would be flopping about, doubled over from the laughter.

Still, Justine's dispassionate expression never changed.

As David R. began to pass out, he faintly heard someone say "That's enough, Justine. Feed him oxygen. The carrier's done its work. Let the rider settle in, do its work now."

Hope he doesn't forget my bloody tooth, David R. thought.

And then the darkness closed in.

Mr Tilley

Behind his gasmask, Mr Tilley watched as David R. began to pass out from the gas.

"That's enough, Justine," he said. "Feed him more oxygen. The carrier's done its work. Let the rider settle in, do its work now."

Justine obediently made adjustments to the gas feed. David's breathing came more easily, although he remained nearly unconscious, his pupils dilating, his eyelids fluttering, trying to close.

A few moments later, Mr Tilley knew the rider had done its work; David R.'s body shuddered slightly, then relaxed again as his last shreds of volition gave up. He looked down at David R. His trousers had a massive bulge.

"Now," Mr Tilley said, "we'll have to do something about his erection. We'll bring in Kelly Tan for that."

He leaned over David R. to check his eyes beneath the eyelids.Pupils hugely dilated, he thought to himself.He's ready, and we will complete the imprinting now.

"David," said Mr Tilley, "wake up now, please."

David R. slowly opened his eyes. Like Justine's eyes, they were impassive, almost empty.

"Good, you're responsive," Mr Tilley said. "Now, listen to me. You cannot do me harm, any more than I will do you any harm. Do you understand me? You may speak."

"Yes," said David R. in a monotone voice.

"Whatever else happens, you will never be able to do anything to me that can harm me. Do you understand?"

"Yes."

"Good, good," Mr Tilley said. "And now, I think we'll begin. Justine, the signals to Beverley, Sadie and Helga."

Justine picked up the extension.

Sadie and Beverley

The maintenance and airconditioning room was on the top floor, near the roof maintenance ladder and access to the roofspace.

Here, the airconditioning throbbed and thrummed steadily, drawing in air from outside and distributing it throughout the complex.

Beverley and Sadie were ready. Beverley was a tall nurse with fair skin, a thin face and shoulder length frizzy red hair; like Sadie, Justine and Helga, she had been here for as long as Mr Tilley had been working with the practice.

Like the others, Beverley had been conditioned and exposed to his gases countless times, to the point where she did not know which were her thoughts and which the commands of Mr Tilley.

The little light next to the extension flashed red, then stopped. Beverley and Sadie glanced at one another.

"Masks," Sadie said. Beverley reached for her mask, slipped it on as Sadie did likewise.

"Ready?" Beverley asked.

Sadie nodded. "How's the payload?"

Beverley nodded towards the thrumming air conditioning unit. Three large coloured gas cylinders stood upright in a metal frame, a complicated arrangement of feeds and tubes linking them to one of the air conditioning intakes. A control panel bore three little chrome wheels, one red master control wheel and a gas mixture readout.

The hookup was ready.

"Signal the surgery," Beverley said.

Helga

The extension rang. Helga picked up the phone, listened, nodded.

"Yeah, okay," she said, hanging up. She turned to Miss Mostyn, leaned across, stubbed out the cigarette she'd been smoking in the ashtray on the table.

"'Scuse me," she said, leaving the room.

Mr Tilley

Mr Tilley watched as Justine called the staff room.

"Helga?" she said, her voice muffled by the gasmask. Then: "Come to Mr Tilley's room." Then Justine hung up.

"Good good," Mr Tilley said. "When she gets here, we'll mask her. This way, Sarah'll think you misdialled the staffroom and got the wrong extension." He smiled. "Wouldn't want your little spy cottoning on too soon, now, would we David?"

"What ..." David R. struggled to say.

"Interesting, resistance," Mr Tilley said. "Soon sort that out."

The door opened, and Helga walked in, without a mask. She crossed over to a storage unit, took out a gasmask, put it on.

"Ready?" Mr Tilley asked.

"Ready," Helga replied.

"Ready," Justine said.

"Well, then," Mr Tilley said, "let's get the show on the road." He looked at David. "Justine, take him off the vent, put a mask on him first." As Justine reached for another gasmask, Mr Tilley leaned over David R. again.

"Don't want you to overdose, now," he said. "Remain where you are. Relax. Let your body just relax and sink into the seat."

David R. found his body complying, even if his mind wasn't.

Justine removed the vent, slipped the gasmask over the unresisting David R. and adjusted it. When she was ready, she stood up and crossed back over to Helga, who stood impassively beside the phone.

The extension gave two rings, went dead.

"Justine," Mr Tilley said. Justine gave the extension to the aircon room two rings, hung up.

"That's it," Mr Tilley said. "Now all we do is wait for the gas to start. How many people were in reception?"

"Sarah the receptionist, the blonde girl, the suit, the Keeley lads – you know, the twin College students, Miss Mostyn in the staff room, Kelly Tan in the Recovery Room and Rosamond Callas," Helga replied.

"Rosamond Callas?" Mr Tilley asked.

"She just dropped by. She wanted to see you about something," Helga said. "She was talking to Sarah a few minutes back. She looked very angry."

Mr Tilley chuckled. "She won't be in a minute."

Beverley and Sadie

The wall mounted extension rang twice, flashing red. It went dark. Beverley and Sadie looked at one another, then at the aircon unit.

"Time to get started," Sadie said.

Beverley crossed over to the control panel, checked the gas mix proportions were correct, and slowly turned the red wheel, letting the gas vent into the air conditioning system.

"In about a minute," Beverley said, "the gas will fill every room in the surgery."

Sadie listened to the whooshing as the gas mixed with the air, carrying it through the ducts into the rooms where the unsuspecting patients, Sarah C. and Miss Mostyn sat.

"Buckle up," Beverley said, "you're going on a hell of a ride."

Sadie smiled. "Nighty night."

Reception

In Reception, the customers sat waiting. Sarah C. sat at the desk, filing her nails, bored. There hadn't been a phone call for half an hour, and all the filing was done.

Sarah C. was glancing across at Rosamond Callas, who sat across from her, watching the door to the surgeries, apparently fuming.

The other customers – Piper Connors, the blonde girl in the townie getup, James and Robert Keeley, Marsha Winstone the City girl – were starting to look bored and exasperated. But then, this was a dentist's office. Boredom and exasperation were to be expected.

The clock above Sarah C. ticked. The TV droned on at reduced volume, looping the same adverts over and over.

Over their heads, unnoticed by everyone, colourless, odourless gas began to pour gently into the room.

Staffroom

Miss Mostyn sat, reading a magazine she'd bought earlier that day. The room was otherwise empty, silent.

Miss Mostyn had no idea the room was slowly filling with gas.

Mr Tilley

"I wouldn't remove your masks right about now," Mr Tilley said to the girls, before glancing up at the air conditioning grille above their heads. "Things just got interesting."

Robert Keeley

"Does anyone know where the bogs are?" Robert said, standing up suddenly. Everyone stared at him, including his brother.

"Never mind," he said, making his way across the room towards the nearest door.

"No, wait," Sarah C. said. "That's not the toilets, that's the Recovery Room –"

Too late, Robert was already through the door.

Piper Connors, Townie

Shit, I wish I didn't have to do this, Piper thought, as the time ticked by.If I leave here, the Practice'll charge me a fine, and my wisdom tooth willstill have to come out. She sighed.Wonder if there's a smoking room round here?

She found herself glancing across at the other lad, who looked like the brother of the lad who'd got up to go to the toilet.

The brother saw her. He was smiling.

What's he smiling for? Piper asked herself. Then she realised she was smiling too. There was something so stupid about this lad's dopey grin that she just had to laugh.

Then she saw that he was also laughing.

"What are you laughing at?" Piper said, giggling.

"You," replied the lad, between guffaws.

Robert Keeley

Robert barged into the room, looked around. It wasn't the toilet. The room, in fact, was in half darkness; the blinds had all been drawn and the lights were off.

He saw somebody in the room, sitting on a seat on the wall beside him. Robert smiled, laughed nervously.

"Oh, sorry, my mistake –" he said.

The figure didn't move. Robert turned, thought of something, glanced back. He stared.

There was a crazy woman sitting in the recovery room, all alone, doing nothing, wearing what looked like a gas mask.

Chuckling, Robert turned back. The Receptionist bumped into him.

"Hi," he said.

"Look, sorry, this is the Recovery Room," said the girl, smiling. "The toilets are the other way, over there." She pointed back across the room. "Just leave the patient there to recover in peace, all right?"

Robert chuckled some more. "Recover from what? Schizophrenia?"

Sarah C. frowned. "What do you mean?"

"In there," Robert said, feeling a knot of laughter rising in his chest. "A girl with a g ... wearing a g ..." He jerked his thumb back into the Recovery Room. Sarah, oblivious to the fact that she was smiling broadly from ear to ear, brushed past Robert as the lad began making his way across the room towards the clearly marked toilets, trying to stifle his laughter.

Sarah C. had no idea of what was happening in both this room and the Recovery Room. Even if she did, she would not have known that from her vantage point on the threshold of the Recovery Room she was, in fact, standing directly underneath one of the airvents which was, at that minute, flooding the room, and her lungs, with gas.

All she was aware of, and that only marginally, was a cooling streamer of air from above, brushing loose strands of her hair, wafting down past her face.

Mr Tilley

When Robert Keeley let out a whoop of laughter, the sound carried up the corridor to the open door of Mr Tilley's surgery.

It reached the ears of Helga, Justine and Mr Tilley.

"And there you go," he said.

Miss Mostyn

The laughter caused Miss Mostyn to look up. She realised she'd been chuckling since the cartoon page. She was looking at a medical section on throat cancer; a deadly serious article.

Miss Mostyn couldn't stop laughing. Something about that cartoon earlier had tickled her.

Sarah C.

Sarah returned to her seat, feeling a tickle at the back of her throat erupt into a loud giggle. This wasn't dignified. She sat down a little heavily, and the chair span, nearly throwing her off. The giggle became a whoop of laughter.

She looked at the rest of the room. They had turned from staring at Robert, who was laughing out loud himself now, halfway to the toilets, leaning against a wall, and were now staring at her.

"Whoops!" Sarah C. cried, giggling.

Across the room, Robert's brother James' laughter began explosively, the snort ripping from his mouth and nose followed by a great bellow. Next to him, Piper Connor tittered delicately. Marsha Winstone's laugh emerged, a low, throaty chuckle.

The last vestige of Sarah C.'s composure gave way. She howled with laughter, slowly sliding off her seat.

Miss Mostyn

It was useless to resist. Miss Mostyn found herself crying with laughter, tears streaming down her face. Bending over herself, she flopped over onto her side on the long upholstered seat.

Mr Tilley

"All right," said Mr Tilley to Helga and Justine, "you can now dress to greet the patients."

Helga began to unbutton her uniform, as did Justine.

"Stop," Mr Tilley said. "Why not let David see?" He gestured. "Stand where he can see you both."

Justine and Helga moved over to stand squarely in David R.'s field of view, standing square on to him, their faces impassive as prostitutes beneath the masks.

And then, as he watched, they slowly began to remove their uniforms, unbuttoning them one at a time, revealing their gorgeous, firm bodies beneath the deliberately tight uniforms.

Mr Tilley stared distractedly at the clock. "Okay, time for the next phase, girls. Helga, when you're suitably dressed, go and get Miss Mostyn. Take your time going through Reception. Let them see you."

Sadie and Beverley

Sadie checked her watch. "Okay," she said, "shut down the laughing gas, then the rider."

Beverley turned wheels, shutting down one component, then the next. Finally, she shut off the main gas feed.

"Everyone downstairs not wearing a mask is going to be pretty zonked by now," Beverley said. "Let's go down and get them ready."

Slowly, they began to undress in front of one another, stripping first down to bra and panties, then unclipping one another's bras to reveal their gorgeous breasts, and finally slipping off their panties to stand naked, facing each other.

"Okay," Beverley said. "Let's go."

Helga

Wearing nothing but her gasmask, Helga left the room, walked slowly and deliberately down the corridor through to Reception.

Reception was in chaos. Everyone was laughing for no apparent reason. Sarah C. had slid off her seat and was crawling along the floor trying to get to the exit. The townie girl and one of the two lads were collapsed into each other's arms, using one another for support. The woman in the business suit and the other lad were sitting on the floor; the boy slumped in place, a spreading stain around his crotch, and the woman because she'd slid off her seat and sat there, her slender, swarthy legs akimbo, howling with laughter at the indignity.

Turning, Helga walked slowly through Reception to get to the staffroom. People noticed. Some pointed. If anything, it was even funnier than before.

Mr Tilley

"Justine," Mr Tilley said, "go and fetch Miss Tan here from the Recovery Room. Enjoy exposing your gorgeous naked body to everyone in Reception. Have fun."

Justine slowly walked out, leaving Mr Tilley and David R. alone in the room.

"You know," Mr Tilley said, "all of this is for you, David. The gas; the masks; the conditioning, the nurses undressing; all of it."

He leaned over David R. "You've been following a story, and it was getting a bit too close to me for comfort. So I have to do something drastic to deal with you now, I'm afraid."

David R.'s face remained impassive.

"Let me tell you about a little shindig I set up a little over two years ago. Remember? At the College across town?"

Two Years Earlier:

The College Orgy

Nobody had a clue how it all happened. It just did. In the middle of an ordinary end of year celebration, a disco the Students' Union had put on for everyone to celebrate the end of the exams and the forthcoming start of Summer Break, something bizarre began to happen to everyone, students and staff alike, who happened to be inside the Students' Union at the time.

Without warning, everyone in the building began to feel very strange, very relaxed and heavy. Heads began to nod; eyelids began to close, and people stopped where they stood, even in mid conversation, staggered, and began to sink to the ground, unable to remain awake.

Everyone was affected, from the barman behind the counter to the DJ. Everyone began to feel very, very sleepy.

No-one who told the tale afterwards could remember how long they were asleep. All they knew was, when they woke up, they woke up next to different people to the ones they'd come to the party with.

Engaged couples woke up on opposite ends of the room, each next to people they secretly wanted to shag. Shy men woke up straddling gorgeous women they wanted to ask out for a date, but had never had the courage even to approach.

Andeverybody woke up horny.

Oh, and there were some real freaks at the end of the hall where the DJ's booth had been set up. Some women and a man, all of them standing there, naked. Nobody knew what they looked like; for some reason, the memory of faces was a complete blur.

And then the DJ put on some sort of music, and everyone started dancing slowly, bumping and grinding, removing one another's clothes teasingly, one at a time. The fiances and fiancees gleefully fell into the arms of the couples they had desire for; the gorgeous women reached for the terrified geeks and embraced them in passionate kisses. Even the freaks got into the act, dragging out two fresh-faced eighteen year olds and strapping them down while young men fingered and licked them to orgasm in front of a roaring audience.

There had been repercussions, of course. Engagements broken off; surreptitious visits to Family Planning Clinics and, surprisingly enough, Confessionals in churches all over town.

The press had been slow to cotton on to the enormity of the news: like the participants, they'd been caught with their pants down.

But some people had begun to put two and two together, and some of them were starting to come to some disturbing conclusions.

Enter David R.

Reception

Already, some of the patients were on the verge of passing out, their laughter subsiding. Marsha Winstone and Robert Keeley were already entering the entrancement stage; James and Piper were still giggling, clutching to one another, and Sarah was deeply under, further than the rest of them.

Justine wandered through Reception, giving the two remaining conscious people a good look at her gorgeous naked body, her flawless ebony skin, its gracious curves. Justine's breasts were large, rounded globes topped with large, dark erect nipples; her bush was a triangle of dark thatch surrounded by sweat glistening skin as her own arousal flushed her dark skin.

James stared at her openly, giggling. Piper elbowed him in the ribs, but she too could not stop staring at Justine.

As Justine walked past them towards the Recovery Room, Piper's and James' giggling began to subside as they, too, found their eyelids begin to close, their heads nodding and their descent into entrancement under way at last.

From his first experiments across town, with a mother and daughter, Mr Tilley had discovered that some people were a little more resistant than others: those with a lower sex drive, for example, were less prone to fall into trance and required some stronger inducements such as vials of concentrate broken under their noses to facilitate the deeper levels of trance that were required to implant lasting imprints and suggestions.

Mr Tilley

Mr Tilley opened the blinds, opened the window to his surgery. A few minutes later, he removed his gasmask and breathed clean air.

"You see, David," he said to David R., "it's all about the libido. I've been working with the human libido for a long time, and it was a chance discovery of the effects of my experimental drug that led me to develop it further, to the extent that I have a fairly good grasp of what it can and cannot do.