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"I was going through anything I could get on Pike" Jim started to explain, stumbling over some words in his excitement, "and at first it was really difficult, because there was barely any information on his work on parallel universes, and – "

"Jim" Bill interrupted him calmly. "Please. What have you found out?"

John didn't doubt that he had stopped the IT tech because he could tell their friends were getting impatient.

Jim blinked.

"Right. Sorry. So, Pike has been theorizing – "

"Theorizing?" Mike asked. "Theorizing? All that money they must have spent on him and they didn't even want to see results?"

John could see Sherlock smirk from the corner of his eye and suppressed a smile himself. They both vividly remembered Mycroft coming to see them to give Sherlock a file after he had been forced to visit several secret labs in and around London – he had let show that he was upset, and he had muttered about "no results whatsoever and yet they insist on paying them money". Apparently Mike was of the same opinion.

Sadly, Trevelyan seemed to either have managed to build a device to transfer them into a parallel universe without the Secret Service's or the Government's knowledge – which was likely, otherwise Mycroft would have warned them – or he had been paid to create such a machine, to what ends John couldn't say.

Jim cleared his throat and tightened his grip on the papers in his hand.

"Yes, theorizing. Pike went through a lot of data that, quite frankly, goes over my head, but he insisted that parallel universes existed and that it would be possible to cross from one to another. However, he advised against any attempt to cross dimensions."

Even before he continued, John could feel dread pool in his stomach. If a scientist, who should have been interested in finding out if his theories were correct, didn't want anyone to try –

"He thought that if one "tipped the balance" in the other universe, that it could create immense complications, changes, in the dimension one came from".

""Tipping the balance"" John repeated, "and by that you mean –"

"Murder".

Sherlock's voice was quiet, but the word seemed to grow in strength as it travelled through the flat, only becoming louder and louder to the people who listened.

"Amongst other things" Jim replied, "He thought that other happenings, such as an election gone wrong – remember, tipping the balance, once voice would be enough for that – or something as simple as accident occurring when nothing should have happened – "

"We get the picture" Sherlock interrupted him briskly and began to pace up and down the living room. Jim watched him, and trying to comfort him, said, "I know it's dangerous, but at least there has been no –"

He caught Bill's eye and stopped.

"What happened?"

"Pike" he answered simply. "He was killed this morning."

Jim cursed. "And he was the only lead you guys had to – "

"Jim" the other man warned, and the IT tech closed his mouth, looking sheepish.

"Changing one universe by disrupting the order of the other" John, who had been silent until now, muttered. "He already did that. It certainly gives him one more motive for Pike's murder".

The doctor turned around and watched his friend pace. They knew they were thinking the same thing – how much could their world have changed? What difference had Pike's murder caused? And what could Trevelyan possibly hope to achieve by changing things?

"Can he control it?" Sherlock asked, standing still. Jim stared at him and the consulting detective repeated, "Can he control it? Has he any way of knowing what he changes?"

He shrugged. "Pike hadn't gone that far, I think. At least I couldn't find anything on it..."

"So we have to find Trevelyan, somehow change back whatever he changed, if he changed anything at all, and get you home?" Bill asked.

"Yes" Sherlock confirmed, as if it was the easiest, most logical conclusion, and John thought that it might be, for him at least.

"First of all let's find him" John, the consulting detective, stated, "then we can try to find solutions to our other problems."

The doctor nodded at him and, since Sherlock had begun to pace again, caught his sleeve. He dragged him into a corner, certain that Bill, with Mike's help, would insist on giving them some privacy.

"What are you thinking?" he whispered. Sherlock's shoulders were tense, his jaw clenched; John knew the signs. The consulting detective was stressed, more so than their situation could explain, at least at the moment.

"A life for a life" he replied simply, as quietly as he could.

"Sorry?"

"A life for a life, John. If Trevelyan can control the changes – we know he is a madman. Why else would he have used people as guinea pigs the way he did? And one madman might use a life to save that of another madman".

Even before John completely understood what Sherlock meant, he paled.

If he hadn't been expecting it – if Mycroft hadn't told him what Trevelyan thought he could do – if he hadn't been confused and trying to grasp what was going on – he wouldn't have felt it.

But as it was, he could feel a ripple.

He didn't know how else to describe it; he was standing next to the British Government, looking at Mycroft, waiting for him to elaborate, when he suddenly felt a movement in the room, in the air, like everything was shifting slightly to the side.

He stared at Mycroft, and the other man nodded to show he had felt it too.

"Keep it" he ordered.

"What?" Greg asked, confused, because whatever he was supposed to remember couldn't be important because he had already forgotten –

"Greg. The dizziness".

Right. He was dizzy. He rubbed his head. How could he have forgotten? He was still dizzy –

"Remember. It is important".

"Why?"

"Because otherwise we couldn't help Sherlock and John."

"But Sherlock – " what he had wanted to say escaped him as he remembered that the consulting detective and his blogger were stuck in a parallel universe and that they had to get them back.

He shook his head to clear it and raised a hand when Mycroft began to speak.

"I know, Mycroft. Sherlock, John, parallel universe. I have it now." He frowned as he tried to understood what had just happened.

"What's going on?"

"I just told you that Trevelyan might attempt to change our universe by influencing another. He seems to have succeeded."

"That – that was things changing?" Greg stared at the wall as he tried to figure out if anything had changed. He remembered everything as he had before, but he couldn't be sure; if it was changed, these changes would have been normal, would always have existed, and what was normal would have been strange, and he couldn't –

"Don't" the British Government said slowly and clearly. "Don't try to remember if anything has changed. If I am correct, we are the only people who still remember things the way they were."

"But why?"

"Because we knew they could be changed. From the moment I told you it was possible, the information was in your consciousness, and therefore when things did change you noticed."

Greg sighed.

"And I thought working with Sherlock was complicated." He took a deep breath and continued, "What now? Are we still investigating Sherlock's and John's disappearance? I mean, we must be, or we wouldn't be here, and –"

"Greg."

The DI reminded himself that he wasn't supposed to think about the confusing events that had led to this point and closed his mouth.

"It will be best to return to my office" Mycroft began, taking his phone out and presumably sending a text to his driver, "and to conclude what has been changed from there. Under no circumstance – "

"Don't worry. I know what I have to do. Remember".

The British Government nodded and turned around without another word, strolling out of the lab. Greg followed him.

He was strangely relieved that the driver that awaited them was the same that had brought him here. On the drive to Mycroft's office, he realized that remembering would be more difficult than he had thought.

There was a part of him that wanted to forget about the dizziness because it would be easy; that wanted to sink back into the familiarity that was calling out to him. Now, he felt off, like something was wrong, because it was.

Sherlock and John needed his help. He kept repeating the phrase in his head until it had become an automatic reminder of the shift that had taken place.

Greg wondered if Mycroft suspected what had happened. Probably. This was Mycroft Holmes, after all.

He was proven right when Mycroft left the car without a word and went straight to his office, ignoring his employees and leaving Greg to hurry after him.

When he entered the room, Mycroft was already typing into his computer. He stopped abruptly and stared at the screen

For a few moments, silence reigned.

The British Government raised his eyes to meet Greg's.

"Jim Moriarty disappeared after he had discredited Sherlock".

The Secret Service had recovered Moriarty's body, Greg knew. If it hadn't been found, if Moriarty had disappeared –

The consulting criminal could still be alive.