Martin Scorsese's seminal 1975 drama Taxi Driver informs this tale of a neglected, Upper West Side outcast who slowly devolves into a potential murderer. John Leguizamo stars as Seymour, the mentally-challenged self-proclaimed "king" of the film's title. He's still in the care of his mother Mona (Julie Carmen), who is a protest organizer against their neighborhood's corrupt police practices. Although Mona lives happily with her lover Joanne (Rosie Perez), her ex-boyfriend Jack (Cliff Gorman) often shows up to antagonize the household, Seymour in particular. His assertion that the unstable young man is faking his malady only sends Seymour into an unpredictable rage. Shortly after the film's production, writer-director Seth Zvi Rosenfeld married his rambunctious star Perez; their friend Annabella Sciorra shows up in a supporting role.