Thrown thirty-five years into the past, Derry and Taylor Brandon have the chance to alter the events that ended humanity. Easy, right? All they have to do is track down a father who hasn't conceived them yet and convince him of who they are and that he has a hand in destroying the world. Then they'll be able to fight the man who has tormented them in their own time—and now in the past—and confront and conquer their personal demons along the way.

Piece of cake.