Psychiatrist Kara (Julianne Moore) does not believe in the existence of multiple personality disorder, but her father (Jeffrey DeMunn) asks her to diagnose a strange case of multiple personality disorder. The patient David (Jonathan Rhys Meyers) has a mild personality, but he instantly becomes a tough Adam after receiving a call. Puzzled, Kara drove to the former residence of the personality David and learned that the real David had died in a strange murder many years ago. Kara was eager to find out the connection between Adam and David, but at the same time she found that her colleague died strangely, and a cross similar to the one on Adam/David appeared on the back of the corpse. The seemingly simple medical case was instantly shrouded in the shadow of the supernatural world, and even Kara's father could not escape the curse. What is the truth behind this?