Matt (Josh Hartnett) tiene un problema: desde que lo dejó con Nicole (Vinessa Shaw) sus relaciones sexuales no son nada fructíferas. Por ello, animado por su hermano y confesor John (Adam Trese), decide pasar su propia cuaresma: 40 días y 40 noches sin sexo. Mientras su compañero de piso y amigo Ryan (Paulo Costanzo) hace una apuesta en el trabajo sobre si logrará o no superar tanto tiempo sin sexo, Matt conoce a Érica (Shannyn Sossamon) y se enamora de ella. Obviamente, no puede acostarse con ella o perderá la apuesta.

When Father Joseph Hennessey visits the home of one of his parishioners to offer last rights,he becomes embroiled in a plot which ultimately shakes his faith to its very foundation. Intrigued by the dying man's mention of "Nim," and fascinated by the man's saintly demeanor, Father Joseph's curiosity is redoubled when a beautiful young woman enters his church to question the young priest about the deceased man. Father Joseph and the woman, whom he discovers to be the "Nim" in question, embark upon an investigation into the circumstances surrounding the man's death.