Confessions of a Sinful Nun centre on the 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 being with another woman. This attraction and desire will shatter everything she believes in. Meanwhile, Mother Superior (Nina Hartley) will have to deal with other outbreaks of forbidden and salacious behaviour among the other sisters...