“The Little Hours” is based on a story from a collection of novellas titled “The Decameron,” and it was written by Giovanni Boccaccio long before there was a New York Times best-sellers list. Boccaccio’s work was composed in the 14th century.

Boccaccio’s “The Decameron” features 100 tales covering a wide range of topics told by a group of men and women. For the new film adaptation, writer/director Jeff Baena (“I Heart Huckabees”) has taken a bit of the original collection and turned it into an offbeat blend of a 14th-century cautionary tale with a satirical modern touch. The result is not as whimsical as a Mel Brooks period piece but does brush up against enough farce to make it fun.

“The Little Hours” unfolds in a convent during the latter part of the Middle Ages where most of the nuns are unstable. Alessandra (Alison Brie) has been sent to the convent while her father (Paul Reiser) tries to pull together a dowry that will most likely never happen. She’s friends with Genevra (Kate Micucci), a virgin hiding a dark secret about her religious history.

They tend to follow Fernanda (Aubrey Plaza), a nun completely lacking in grace, love for her fellow person, commitment and religious passion. If the film was set in a modern office building, she would be the worker most likely to go crazy and kill her fellow employees. This anger is mixed with a mysterious need to head into the woods late at night with the convent’s donkey.

These three are so abusive (using a language that’s salty for the 20th century) to the convent handyman, he quits. When Father Tommasso (John C. Reilly) runs into Massetto (Dave Franco), a young man in need of a place to hide, he comes up with a plan to have him take over as the handyman. Massetto will pretend to be deaf and unable to speak so he can avoid conversations with the nuns.

Talking is about the only thing Massetto doesn’t do with the nuns.

Baena bounces the players through a bizarre series of events that deal with love, lust, witchcraft, religion and elements that don’t often appear in a tale set in a convent. The way Baena has written and directed the movie, it plays more like a modern tale of sexual antics. Part of that is the modern language his characters use as verbal weapons and part is the very aggressive attention to breaking as many Commandments as possible.

It works because Brie, Micucci and Plaza attack the roles with unbridled energy. Micucci has made a career out of playing quirky characters but they all pale to the absurdities of her Genevra. Plaza always looks like she’s having a wicked good time when she gets to play a character who lives to defy the rules.

A word of warning. “The Little Hours” is an assault on conventional religious thinking that will most likely shock those who expect this movie to show any respect toward the Church. All this movie shows is that girls just want to have fun even if it is the Middle Ages.

MOVIE REVIEW

“The Little Hours”

Grade: B

Starring Alison Brie, Aubrey Plaza and Kate Micucci. Directed by Jeff Baena.

Rated R for graphic nudity, language, sexual content, drug use. Check listings for theaters. 1 hour, 30 minutes.

Bottom line: An assault on religious thinking showing girls just want to have fun