Jerry (Ryan Reynolds of GREEN LANTERN, VAN WILDER) works at a faucet factory in the town of Milton. He's schizophrenic and hears voices if he doesn't take his medication In fact, the two main beings he has conversations with are his dog and cat, who give him life advice. Jerry has a crush on a girl at work, Fiona (Gemma Arterton of CLASH OF THE TITANS), but accidently kills her after she stands him up on a date. He takes her body back to his apartment, cuts her up and puts the remains in tupperware containers. He keeps her head in the fridge and regularly talks to it because he believes she's still talking to him. Then, he gets involved with another girl from work and soon there are two heads in the fridge. Via flashbacks, we find out that he stabbed his mother when he was a kid and spent most of his life in a mental facility. Eventually everything catches up with him as he continues to stay off his medication and kills.
This is an odd movie, a black comedy that has clear influences from two Anthony Perkins movies, PSYCHO and PRETTY POISON. There's even a musical number, in case it wasn't weird enough.