Unforgettable

As it ticks through its genre tropes, you keep hoping that Unforgettable will become something other than what you expect. But it never happens.

Instead, this tawdry psychological thriller feels like a run-of-the-mill cable television potboiler about vengeful affluent housewives that’s devoid of subtlety and surprise.

Divorce can be hard on children, but it’s the adults battling for the affections of young Lilly (Isabella Rice) who seem to have the most difficulty coping with the new arrangement.

Her father (Geoff Stults) is running a successful small-town brewery and trying to rebuild his family with Lilly and his new fiancée, Julia (Rosario Dawson), who’s adjusting to life away from the big city and trying to move on from an abusive relationship in her past.

None of this sits well with Lilly’s condescending mother, Tessa (Katherine Heigl), who’s still reeling from the breakup and resents the restricted access to her daughter. So she targets her fury at Julia by unleashing an elaborate revenge scheme, both online and in person, with gradually escalating ramifications.

The directorial debut of veteran producer Denise Di Novi (Ed Wood) features some stylish visual touches, although that hardly seems necessary to support material that allows the mayhem to play out with a straight face, inviting snickers instead of gasps as its silly twists are unspooled.

The screenplay by Christina Hodson (Shut In) attempts a half-hearted examination of gender politics, absentee parenting, social-media privacy, and even mental illness. Yet it seems oblivious to the fact that its best moments are of the campy and catty variety.

Dawson and Heigl develop an amusing adversarial chemistry as the film becomes completely detached from reality and builds to its inevitable final confrontation — no spoilers here — punctuated by bloody comeuppance.

Stand-up comedian Whitney Cummings, playing Julia’s snarky best friend, scores a big laugh by referring to Tessa as “psycho-Barbie.” And former “Charlie’s Angels” star Cheryl Ladd, playing Tessa’s overbearing mother, chews the scenery effectively while refusing to take this mess seriously.

The target demographic appears to be the Fifty Shades of Grey crowd, who’ll find it both too tame and lacking in tension. Ultimately, Unforgettable is just the opposite of its title.

Rated R, 101 minutes.