An exploration of the life and work of the legendary neurologist and storyteller, as he shares intimate details of his battles with drug addiction, homophobia, and a medical establishment that accepted his work only decades after the fact. Sacks was a fearless explorer of unknown mental worlds who helped redefine our understanding of the brain and mind, the diversity of human experience, and our shared humanity.

Dr. Malcolm Sayer, a shy research physician, uses an experimental drug to "awaken" the catatonic victims of a rare disease. Leonard is the first patient to receive the controversial treatment. His awakening, filled with awe and enthusiasm, proves a rebirth for Sayer too, as the exuberant patient reveals life's simple but unutterably sweet pleasures to the introverted doctor.