Sam Foster (Ewan McGregor) is a young psychiatrist who is filling in for a colleague on leave. Among his new patients is Henry Letham (Ryan Gosling), a young art student who hears voices and is seriously contemplating suicide. This resonates strongly with Sam, who rescued his painter girlfriend, Lila (Naomi Watts), from a wrist-slashing. The extremely volatile Henry begins to threaten Sam’s hold on his own sanity, as he races against time to figure out the truth about Henry’s past, the source of his troubles, and the cause of the seemingly unexplainable things that are happening to both of them. Sam investigates the ghostly figures of Henry’s life, including Athena (Elizabeth Reaser), the girl Henry loved, and also his parents (Bob Hoskins and Kate Burton), uncovering ever more disturbing idiosyncrasies along the way.