‘Sister Mary’ Gets Your Attention

A heavenly and hellish performance by Diane Keaton is the best reason to watch “Sister Mary Explains It All,” Christopher Durang’s slow-starting but satisfying adaptation of his irreverent play about the vagaries of Catholicism.

Keaton effortlessly captures the rigidity and self-righteousness of this tart, intimidating nun who bullies both children and adults. She even carries a List of Sinners that includes Elizabeth Taylor, Roman Polanski, Truman Capote and, yes, the editors of National Geographic.

Sister Mary doesn’t question what the Catholic Church says about Jesus, mortal sin or the Ten Commandments. Those she likes are rewarded with a cookie. Those she dislikes are reminded about the fires of hell.

The film opens in 1969 as four cute kids appear in a Christmas pageant about the life of Christ. Fast-forward 25 years later as this quartet of troubled adults resurfaces at Our Lady of Perpetual Sorrow School, where they hope to humiliate Sister Mary at her annual Christmas lecture.

Each of the characters, played by Laura San Giacomo, Brian Benben, Wallace Langham and Jennifer Tilly, has suffered in some way over the last two decades and found themselves questioning the Catholic doctrine they learned as youngsters. Needless to say, Sister Mary fails to grasp their frustration. And she has no intention of giving them a cookie.

Directed by Marshall Brickman, this polished production takes a half-hour or so to really grab us by the throat, but once it does, there’s no turning away. Giacomo, Benben and Langham are fine, but Keaton is the engine that drives it from start to startling finish.

* “Sister Mary Explains It All” can be seen Sunday at 8 p.m. on Showtime. The network has rated it TV-14 (may be unsuitable for children under the age of 14).