Tags: Anthony Hopkins | Cuba Gooding Jr. | Donald Sutherland | Jon Turteltaub | Maura Tierney

Within the brilliant mind of primatologist Ethan Powell lies an ominous secret - a deep-seated mystery unsolved by his estranged family and the law enforcement officials who have jailed him for murders that occurred in the jungles of Rwanda.

Highly educated and sophisticated, Powell was affected by years of studying mountain gorillas to the point where he was living among them in the wild, as one of their own. Now, held captive in a brutal prison for the criminally insane, Powell, who has not spoken in years, is remanded to psychiatrist Theo Caulder, who must try to unlock the dark mystery in the mind of what appears to be a madman.

He encounters a series of perplexing mysteries, questions with chilling answers, and shocking psychological truths. Eventually both men are led on an extraordinary journey of self-discovery and Instinct.