Crossing In Time

They say that true love transcends space and time, but what if your lover is murdered, and you're given the chance to go back to warn his much-younger self? She agrees to go, knowing it will kill her in a matter of hours, because it gives her one last chance to be in the arms of the man she loves.

Except... he doesn't believe her. In fact, he thinks she's one fry short of a Happy Meal.

(Oh, and she's supposed to save the world while she's at it. Go figure.)