1900s, USA. Niall and Mick are two struggling psychiatrists. To make money, Mick devises a plan to befriend people and convince them he is not a real person, a figment of their imagination. Niall then suggests they seek therapy from him for their 'imaginary friend'. All goes well until Mick 'befriends' Fiona, and the two vie for her attention. Their scheme takes a crazy turn as they uncover Fiona's dark side.