A teaching nun, who is much concerned with sin in all of its various forms, delivers a cautionary lecture to her charges. One of them, a precocious little boy named Thomas, can quote the Ten Commandments on cue, and each time he does so Sister Mary rewards him with a cookie. But when several of her former students turn up the picture darkens, along with Sister Mary’s indignation. Their stories are disturbingly funny — and it is quickly apparent that one thing they all have in common is their loathing for Sister Mary.