In 1958 New York, Diane Arbus, the daughter of a posh fur store owner, is a housewife and mother who works as an assistant to her husband Allan, a fashion and advertising photographer. One night, Diane's eye is caught by a strange-looking mask the size of a man's head. Later, when Diane gets her first glimpse of her new neighbor, Lionel, in the nighttime street, the mystery only deepens. He is bundled up in coat and hat, his face obscured by a scarf and mask. Only his eyes are visible, frankly returning Diane's fascinated gaze. Over the next two weeks, Diane becomes keenly interested in her neighbor's comings and goings--his footsteps on the stairs, the music playing from his attic apartment, etc. Investigating a backed-up bathroom sink one day, Diane traces the problem to a plumbing pipe linking their two apartments--a discovery that leads to yet more tantalizing clues about the man upstairs. Eventually, tentatively, Diane makes her way up to Lionel's ornate door wearing the Rolleiflex camera that Allan bought her years ago, as yet unused. Diane, however, will not take Lionel's photo that night or the next, when he invites her into his home. It is the beginning of an adventure that will take Diane into the underground worlds that have always called to her--and into a compelling intimate relationship that will transfer her life and her art forever.