To travel realms unexplored (джен)

Peter was not sure why he had agreed to be sent back in time. Or why he agreed to the time travel as a feasible idea in the first place. It really was not his style to potentially sacrifice himself for the greater good, and surely if he succeeded he would cease to exist. They all would. He was not sure the rest of them had thought it through, because if you change the past none of them would continue to be who they were right now. Not that the current situation was any price to be in, but to not exist at all? Because if he managed to change the past, no one would survive as they were today. Sure, their past lives would continue, but not the same and who knows what would happen to them and they guaranteed would not be the same people they were now. He would have laughed at the mere thought if not more or less everyone he really cared for was dead and his own existence had become quite tedious.
or
A time travel AU where Peter does not get quite what he bargained for.