Paul (Francois Cluzet) seems to have it all: a charming hotel on a serene lake, a beautiful wife Nelly (Emmanuelle Beart) and a new son. Forced to work extremely hard to keep things afloat, Paul begins hearing voices in his head questioning the choices he's made. He's convinced that Nelly has been unfaithful and starts to see every male guest as a potential threat. What follows is Paul's downward spiral into the madness of deranged jealousy where he finally discovers that hell is not a state of mind--hell is himself.