The Killer Nun is trash, but not total trash, and that’s a shame.

Anita Ekberg plays Sister Gertrude, a hospital matron whose recent brain surgery has left her morphine-addicted and unhinged. She sneaks out to drink, smoke, and have anonymous sex. She menaces her charges, reprimanding an elderly patient by stomping their dentures to pieces. In bed with a young nun, she orders her would-be paramour to “Say you’re a dirty whore.”

Later, when patients turn up murdered, Sister Gertrude proves the prime suspect.

And here the film lost me. Instead of committing to the crazy and escalating Sister Gertrude’s behavior to ludicrous ends, the script proffers a flimsy mystery. Said mystery proves boring and—for a nunsploitation picture—boredom proves a cardinal sin.