When David rented his quaint San Francisco apartment, the last thing he expected - or wanted -was a roommate. He starts to get settled in to his new place, which has become quite messy, when a woman named Elizabeth suddenly appears, insisting that the apartment is hers. David assumes there must have been some kind of misunderstanding, until Elizabeth disappears just as mysteriously as she appeared. David changes the locks, but this doesn't stop Elizabeth from appearing inside the apartment, mostly to chide David about his messy bachelor lifestyle.
David is convinced that Elizabeth is a ghost and sets out to help her move to the "other side". Elizabeth realizes that she is not in fact dead, and is determined to resist David's efforts to help her cross over. Elizabeth and David work together to try to figure out who she really is and how she came to be in her present state. During this process, the two fall in love.