Zach Clark’s new dark comedy “Little Sister” is a campy, quaint little film that is slow to start, but once it does, has some really touching and entertaining moments. Clark, the film’s writer and director, tells the story of Colleen Lunsford, an aspiring young nun played by “Californication” star Addison Timlin. As Colleen begins to go through her vows and fully commit to the church, she receives a troubling email from her depressive, stoner mother (played by Ally Sheedy of “The Breakfast Club” and “St. Elmo’s Fire” fame). She learns that her beloved brother, who was brutally disfigured by a bomb while on military duty, has returned home to mope, isolate himself and play the drums.

Seizing an opportunity to reconnect with her estranged sibling, Colleen borrows a car from her superior at the nunnery (“Scream Queens” and “Days of Our Lives” star Barbara Crampton). Throughout the film, Clark juxtaposes Christian imagery and themes with pagan and satanic imagery, creating a spooky, gothic middle ground for the film. Clark challenges the idea of the perfect nuclear family by painting a portrait of a midwestern American family with all of its dysfunctions and laying its complicated interrelations out in the open. Standout performances by Sheedy, Timlin and Crampton really bring this world to life, but the film is most memorable for its absurd moments.

“Sister” is marked by bizarre instances of performance art and drug use that feel simply delicious in contrast to the film’s more abundant slow, dry segments, and the soundtrack is sprinkled with angst-filled anthems and screamers that will make any alt punk fan feel right at home. Baby dolls are ripped to shreds and covered in blood, strippers dance, the family embarks on unplanned drug trips and, to save the best for last, two artists dressed in airplane costumes destroy a cardboard model of the World Trade Center in a jarring and deeply unsettling political performance that frazzles the daylights out of Colleen. In an interesting reversal of a common theme, Colleen’s strict Christian values inspire her to rebel against her alternative stoner parents’ drug use, but it isn’t long before she finds herself in the same boat.

The drug sequences are somewhat short and disappointing. The only remarkable thing about Colleen’s mushroom trip is a moment at which she believes her car is full of life-size chickens. Colleen herself is annoyingly timid, but this sets her up well to be the perfect underdog. Still, when she finally dyes her hair back to the vivid fuchsia of her youth and dons gothic makeup for an impromptu performance to cheer up her brother, you’ll wish that it happened much, much earlier in the film.

These key moments are filled with bravery and chaos, which makes the slower parts of the film more meaningful. Still, the film itself is just too slow to start, and when Colleen finally breaks back into her adolescent punk persona, it doesn’t last long enough to leave us satisfied. After all, she appears as a pink-haired, pale-faced Goth queen on the promotional poster, and viewers may be disappointed to discover that they’re actually going to see a movie about a meek, chaste nun who happens to have a wild past that she uses to her advantage. “Little Sister” is a charming but somewhat dull movie that ultimately goes from good to great purely because of its absurdly exciting standout moments.

“Little Sister” will be released in theaters on Oct. 14.

Email Tye Musante at [email protected].