Michael needs a change in his life. When he is told about a clinical trial for a new antidepressant, he signs up on a whim. It soon becomes apparent that the pills have serious side effects, and the tests are abandoned. But Michael refuses to give up his newly found sense of calm and self-control, and he decides to continue the experiment on his own. Intoxicated by his immediate success, Michael feels an urge to take control of other people's lives as well. Slowly, his minor psychological games grow more drastic, until he makes a discovery which forces him to view his actions in a new terrifying light.