Starring Cory Monteith, Amanda Crew, and Gabrielle Miller. Rated 14A.

Sisters & Brothers is more zippily entertaining than Mothers & Daughters and less satisfying than Fathers & Sons, the first two of Vancouver director Carl Bessai’s trilogy of family-fun adventures. This loose-knit ensemble effort repeats some of the same dysfunctional themes and ad-libbed approach—as well as many cast members—from those films, and the results are less interesting as a story than as a series of acting exercises.

The standout subplot here has Amanda Crew and Camille Sullivan as half-sisters, with the former a struggling actor burdened by the latter’s return from rehab. They join forces on a road trip when the budding thespian is invited to an L.A. audition by a fast-talking scuzzball, played effortlessly by Tom Scholte.

Already in SoCal are handsome bros going through an uneasy adjustment to stardom for one (Cory Monteith) and floundering obscurity for the other (Dustin Milligan). Back in B.C., Bessai regulars Gabrielle Miller and Benjamin Ratner reunite as siblings whose tight bond is constantly tested by the brother’s schizophrenia. Jay Brazeau, who has played Ratner’s dad in several outings, is an amusing side character who passes himself off as a lawyer.

Elsewhere, acting great Gabrielle Rose is a middle-aged mom already losing her grip on a surly daughter, played by young Kacey Rohl, when another offspring (Leena Manro)—this one from a fleeting union in India—turns up on their doorstep. Some real emotion is produced here, mainly because Rohl is impressively fierce. But the other sister’s personality isn’t developed, and there’s an absence like that in every story.

The addition of comic-book transitions and determinedly wacky music also guarantee that nothing can be taken very seriously. Given the fragile, this-is-all-there-is nature of improvisation, that leaves these family feuders with a too-narrow tonal range. Something tells me we won’t be seeing First & Second Cousins anytime soon.

Watch the trailer for Sisters & Brothers.