Confessions of a Sinful Nun follows devout Sister Charlotte (Charlotte Stokely) as she lives a peaceful life with her other sisters. Unfortunately, everything will change when Sister Lily (Lily Adams) arrives at the convent. Sister Charlotte is suddenly seduced by the temptation of another woman. This attraction will shatter everything she believes in. Meanwhile, Mother Superior (Nina Hartley) will have to deal with other forbidden behavior around the convent.