Trevor Reznik is a lathe-operator who suffers from insomnia and hasn't slept in a year. Slowly, he begins to doubt his sanity as increasingly bizarre things start happening at work and at home. Haunted by a deformed co-worker who no one seems to think exists, and an ongoing stream of indecipherable Post-It notes he keeps finding on his fridge, he attempts to investigate what appears to be a mysterious plot against him and, in the process, embroils two women in his madness.