Guardians of time, book 1: The named
Marianne Curley2002

Imagine if you were able to change history. By altering one tiny thing you could start a chain of catastrophic events. Ethan is one of the Named, fated to stop this ever happening, although the forces of chaos have other ideas and Ethan is finding it more and more difficult to stay one step ahead. He is also a normal schoolboy, whose life is rapidly becoming far too confusing.

Titre original : Guardians of time, book 1: The named (2002)