Caution: Do not chew gum if you attend "Late Nite Catechism." The Sister has a keen eye out for gum chewers and if she catches you, it could cost you a dollar. Dress modestly, too, lest Sister hand you a lobster bib to cover up.

And brush up on your Catholic church dogma. You would be advised to have at least a familiarity with the doctrine of the Immaculate Conception, understand what the four stages of the afterlife are and what makes a saint. If you can't make that commitment, slouch in your chair and for God's sake, don't raise your hand.

Actor Kimberly Richards portrays Sister in "Late Nite Catechism," a slight spoof that lives or dies on the stand-up chops of the performer and your curiosity about Catholic education and culture. The one-woman show, now playing at Plymouth Playhouse, was written in 1993 by Vicki Quade and Maripat Donovan.

Sister cajoles, scolds and humors her audience. Most often, though, she is an inquisitor in the tradition of a strict catechist. You had best supply sufficient answers or be prepared to enjoy a moment of public embarrassment.

Comparisons of "Catechism" to Plymouth Playhouse's long-popular "Church Basement Ladies" are obvious but not quite applicable. "CBL" finds its humor in narrative — plots with arcs and stories — and familiar characters.

"Catechism" aims to re-enact an experience — the specific recollection of a place and classroom in which you once may have gotten your knuckles rapped (or had friends who did). Marc Silvia's set hits nearly every touchstone of a Catholic schoolroom.

You needn't be Catholic to be amused but it seems to help, judging by a recent weekday audience. They laughed and played along with the gentle abuse from Sister. They were good sports — and honestly, I'm serious about that gum. Sister will stop the show and make you spit it into a tissue. That's for the first offender. All subsequent chewers will pay a $1 fine.

However, even this largely faithful audience lost energy with the thin material. The script lurches and face it, a lesson on stigmata is not inherently funny. Richards at one point barks at us to pinch the person to your left to make sure they're not asleep. That's a telling sign that the air is leaking from the room.

Richards is a terrific and experienced performer. I would prefer a brisker, deadpan character who never dropped the façade of toughness. That reality would make her funnier as a frightening character. The play's conceit, however, has Sister interacting, so perhaps it's better for Richards' warmth and charm.

Was the poor sound system a planned bit that allowed Sister to ask folks, "Who needs headphones?" The usher had to make two distracting trips to fill demand. For those of us who kept our ears naked, the sound was decidedly timid.

Someone in the tech booth owes Sister a dollar.

groyce@startribune.com • 612-673-7299