When they reached the lab on the north pier Rodney helped Zelenka set up his equipment. The work Zelenka had carried out the day before had offered no easy solution to the problem, so the main aim was to figure out exactly what McKay had done to set the machine in motion. Everyone was assuming it had caused McKay's consciousness to switch places with that of his twelve year old self. It was the only logical explanation, and offered some small hope that the process could somehow be reversed.

Soon both Rodney and Zelenka were deeply absorbed. Zelenka was analysing readings from the machinery and trying to figure out what they meant, while Rodney was busy playing with the data tablet and trying to understand how the two very different technologies were able to interface with each other. Rodney was pleased to find that he understood what Zelenka was trying to explain to him. Well, to be totally honest, he didn't truly understand, but at least he began to get the germ of an idea of what he was talking about.

They were trying to change different controls, and see what the effect on various readings was. Rodney was interested to realise that each control entered a low note, just like a musical instrument. By experimenting he was able to play short tunes by pressing different buttons in sequence. By the end of the morning he was starting to feel more confident in what they were doing. He was almost sorry when it was time to stop for lunch.

McKay and Lucas stood in front of Mr Burns's desk, the former looking impatient while the latter simply smirked. McKay wished he'd had the chance to wipe the smile off his face more permanently.

"Fighting in the corridor? I'm disgusted with the pair of you," Mr Burns declared. "What have you got to say for yourselves?"

"This thug was trying to get my project," McKay declared. "He's always picking on me, and I decided it was time I fought back."

"He started it!" Lucas defended himself. "I was just trying to show an interest, and he just turned round and grabbed me, I didn't do anything, honest!"

McKay snorted in disbelief. "Yeah, and your father's the president," he answered sarcastically.

"Shut up," Mr Burns snapped at him. "You ought to know better. I'm calling both your fathers. McKay, you'll spend the rest of the day working on your own in my office."

"But – the science fair!"

"No buts. You've lost your chance. I warned you, I would not tolerate any further bad behaviour from you."

"My project…"

"Your project is a waste of time. I keep telling you, McKay, you're no scientist. Now go get your science books."

McKay could not believe what he was hearing. This was not supposed to happen! "But you can't! You don't understand! I built an atomic bomb!"

Mr Burns's face went white. He stood up abruptly, causing his chair to topple over. "You did WHAT?"

"You know that's what I was interested in, and I thought it was a much better project than the one you and my father wanted me to do, so I went ahead and did it."

"You stupid boy! Have you any idea how dangerous that is?" Mr Burns was almost whispering, as he stared in alarm at the box that he'd so casually dumped onto his desk.

McKay laughed. "Oh, don't worry, it's not a working model."

Mr Burns was staring with terrified fascination at the box. He seemed not to hear McKay's words. "We must evacuate the school!" he declared.

"No, no, no, no, no," McKay interjected. "It's not real. It's not a working model. It's made with silly putty and duct tape. It's only an illustration of how to make an atomic bomb."

"What? Oh. Of course it isn't a working model, you silly boy. You're not capable of making a working model of an atomic bomb." Mr Burns hastily backtracked. "Still, we mustn't have you even playing at making bombs."

"But you thought it was real," McKay reminded him. "So you know I'm capable of the science involved."

"I – Ah – No." Mr Burns appeared to be studying his fingers very closely. "You're in serious trouble, boy. Go to the Principal's office and wait there until your parents arrive."

McKay tried to argue some more, but his teacher was not to be moved. There was nothing for it but to do as he was told. He tried to take his project with him, but Mr Burns would not allow him.

The group ate their lunch sitting in a corner of the lab, with Rodney staring out of the window and admiring the view. He was vaguely aware that John and Dr Zelenka were discussing the situation, but it seemed rather uninteresting to him compared with what had been happening. He was still convinced he was dreaming. Then he realised that they were discussing their Dr McKay, and he tuned back in to the conversation.

"So what is he up to then, do you reckon?" John was asking.

"There is no way of knowing," Zelenka replied. "We can only assume that he is fulfilling the events that have already happened in his own past. We already know that the timeline has not been changed yet, because McKay told you about the time he visited here, so as long as he does nothing to change his own timeline in the past, we know that young Rodney must return to study science and fulfil his own future. We can only hope that our Rodney then returns here."

"But how did the switch happen? How does he switch back?" John wanted answers.

"I am still not sure. It may be that there is a set time limit to the switch. Or it may be that we need to work out how to operate it so that we can manually reverse the change. I really haven't been able to determine which is the case yet."

"It's on a time delay," Rodney interrupted.

"What? How can you possibly know that?" demanded Zelenka.

"That control. That one in the top right corner. It's been changing, gradually, all the time."

Zelenka hurried over to the desk. He bent and studied the controls carefully. "It's possible it's changed very slightly," he admitted eventually, "but how could you possibly notice that?"

"It's easy." Rodney grinned up at him. "You know that the buttons play musical notes? The note related to that control has changed during the morning. The pitch is different. Before, it was a tone above this other control, now it's more like a semitone. If it changes much more it will be the same note."

"Fascinating." Zelenka held his ear closer and listened carefully, then consulted the notes he had made. It's very difficult to see a difference, but I do believe you may be right," he admitted.

"Of course I'm right," Rodney retorted. "I'm always right. But no-one ever believes me."

Zelenka looked over at John and shrugged. John shrugged back. "So we just have to sit and wait?" he asked.

McKay sat in front of the Principal's desk. His parents sat one on each side of him. The Principal, Mr Turner, sat behind his desk with Mr Burns slightly to one side. He was telling his parents just how much trouble McKay had caused the school.

"We just cannot have children bringing bombs into the school," he said.

"It's a non-working illustration of an atomic bomb," McKay explained loudly and slowly, as if talking to someone stupid.

"Be quiet, Rodney, don't make things worse," said his father.

"You're a one to talk!" cried his mother shrilly. "If you'd taken more notice of him perhaps he wouldn't be so out of control!"

"Me? If you didn't spoil the brat, he'd have learnt discipline long ago!"

"Me spoil him? Who bought him that computer? There's a lot we could have done with that money, but you had to waste it on him!"

McKay tuned out and sat contemplating the box on the desk. His whole future lay in the balance here. What had he done wrong? He had thought that if he followed the most obvious course then time would complete its circle and his present and future would be secure. But it wasn't working, was it? He had completed his science project, but had not even had the chance to enter it into the science fair. Now it looked as though far from making life easier for himself he had dropped himself into a whole load more trouble.

Eventually his parents and Mr Turner had run out of steam. His parents were instructed to take him home. He had been suspended from school for a week. He was then to return for the end of the semester, but to work in isolation. McKay thought in despair of what that would mean to him as a child – being able to lose himself inside a crowd was all that had kept him safe so far. Being singled out like this would prove nothing short of disastrous.

He felt numb. He knew he had to figure this out somehow, but right now he was suffering from lack of sleep – this body seemed to cope so much worse than his own – and lack of food. He could see no way out. He silently followed his parents out of the room, casting a look backwards over his shoulder at the box containing his project as he did so. He hadn't even been allowed to take it home with him.

As he went through the secretary's office, he passed Lucas and Lucas's father going into the Principal's office. Lucas gave him a triumphant grin, and dug him in the ribs as he passed. "Boy, are you in trouble!" he crowed. "My Dad's furious with you."

McKay looked up at Lucas's father, and felt his stomach lurch. He looked vaguely familiar, and McKay struggled to remember where he had seen him before – or where he would see him again. Could it be? Maybe everything wasn't lost.

He followed his parents out of school, deep in thought.