Between “Big Love” and the upcoming unscripted series “Sister Wives,” polygamy is fast becoming the dysfunctional family flavor of the month. Add to that “The 19th Wife,” a Lifetime movie about a polygamous sect, set against the backdrop of a murder mystery. Based on David Ebershoff’s novel, the movie makes for an awfully thin gruel, even with a parallel structure that flashes from the present back to a 19th-century woman, Ann Eliza, promised to Brigham Young. Then again, faithful Lifetime movie-watchers have experienced greater hardships than this.

Like the book, the movie alternates between the fallout from a present-day murder and the past, with the showier names reserved for the former.

Queenie Alton (“Grey’s Anatomy’s” Chyler Leigh) lives among the polygamous group, but doesn’t believe that one of the true believers, BeckyLyn (Patricia Wettig), killed her husband. So she joins with BeckyLyn’s excommunicated son, Jordan (“The Good Wife’s” Matt Czuchry), in seeking to exonerate her, even if that means inviting the wrath of the Prophet (Patrick Garrow), who rules over them.

The parallel arc, meanwhile, focuses on Ann Eliza (Lara Jean Chorostecki) and her own struggles as the latest addition to Young’s well-populated harem (hence the title). As structured, though, by Richard Friedenberg’s adaptation and normally reliable director Rod Holcomb, the movie feels painfully flat, failing to stir much interest in either century.

Nor does it help that virtually every theme or beat has been dealt with in “Big Love,” whose central character was expelled from a polygamous compound, as Jordan was; and whose lecherous old coots terrorize their fertile young spouses.

Other than the opportunity to see Leigh in unflattering outfits, in fact, there’s precious little to hold an audience’s attention — and not much in the way of suspense. Mostly, it’s Czuchry’s show, and given the bifurcated format, there’s simply not enough meat to his character.

The most intriguing part actually waits until the closing crawl, providing additional information on Ann Eliza’s post-movie fate. Unfortunately, that sounds like the basis for a more engaging project than the one we just finished watching.

The 19th Wife

Movie; Lifetime, Mon. Sept. 13, 9 p.m.

  • Production: Filmed in Calgary by Sony Pictures Television. Executive producers, Barbara Lieberman, Andrea Baynes; producer, Brian Leslie Parker; director, Rod Holcomb; writer, Richard Friedenberg; based on the novel by David Ebershoff.
  • Crew: Camera, Peter Benison; production designers, Sandy Cochrane, Bill Ives; editor, Victor Dubois; music, Steve Porcaro. 120 MIN.
  • Cast: Queenie Alton - Chyler Leigh Jordan Scott - Matt Czuchry Five - Alexia Fast Ann Eliza - Lara Jean Chorostecki The Prophet - Patrick Garrow Brigham Young - John Bourgeois Mr. Heber - Dave Brown Sawyer Scott - Karl Pruner Hiram Alton - Jeff Hephner BeckyLyn Scott - Patricia Wettig
  • Music By: