In the present, artist Tom Warshaw recalls his traumatic coming of age. As a 13-year-old growing up in New York City in 1973, Tom hangs out with Pappass, a mentally disabled man. With Tom's mother battling depression after the death of her husband, the young boy is left to his own devices. When Tom develops a crush on schoolmate Melissa, Pappass feels abandoned and begins behaving erratically.

Anton Yelchin
as Tommy

Téa Leoni
as Mrs. Warshaw

David Duchovny
as Tom Warshaw

Robin Williams
as Pappass

Erykah Badu
as Lady / Bernadette

Frank Langella
as Reverend Duncan

Magali Amadei
as Coralie Warshaw

Claire Lautier
as Madam Chatquipet

Zelda Williams
as Melissa Loggia

Bernie Sheredy
as Sasha