Twin Souls

Damian spends years thinking his twin was dead, that is until a ghost (not that he knows she's a ghost) tells him he's alive and offers to swap there souls so Damian can bring his brother home.

or

Danny's parents don't react well to him being Phantom and now he's caught in their lab, that is until he hears a voice promising to take him to safety. He wasn't expecting to be faced with a load of bats where he woke.

or or

Danny and Damian body swap!