Annie Landsberg and Owen Milgrim are two strangers who are drawn to the late stages of a mysterious pharmaceutical trial. Each has a different reason for participating in the experiment -- she is disaffected and aimless, fixated on broken relationships with her mother and sister, while he has struggled throughout his life with a disputed diagnosis of schizophrenia. The radical treatment, using pills that the inventor claims can repair anything about the mind, draws Annie, Owen and 10 other subjects into a three-day drug trial that they're told will permanently solve all of their problems, with no complications or side effects. Unfortunately, things don't go as planned.