Marguerite Caine's physicist parents are known for their radical scientific achievements.

Their most astonishing invention is the Firebird, which allows users to jump into parallel universes, some vastly altered from our own.

But when Marguerite's father is murdered, the killer - her parents' handsome and enigmatic assistant Paul - escapes into another dimension before the law can touch him.

Marguerite can't let the man who destroyed her family go free, and she races after Paul through different universes, where their lives entangle in increasingly familiar ways.