Traditionally, the horror movies begins with the tabula rasa and from there builds upwards with little narrative Lincoln Logs stacked on shower scares and mirror pop-ins. Ava’s Possessions shrewdly flips the formula on its head, poising an intriguing conceit in the exploration of what transpires after a ghastly, cathartic event. Where is the werewolf at mentally the morn after the full moon? When do the disfigured, backwoods cannibals run out of human stock and have to settle on Ramen? How nasty a case of PDST results from a Eli Roth-style torture session? What is the aftermath of an exorcism?

Completely unable to recall the events of the last month, Ava’s (Louisa Krause) story begins just as a demon bids farewell to her corporeal skinsuit, beckoned forth with holy water and incantations by your standard rent-a-Catholic-exorcist. Done muttering Latin and squirming in restraints, Ava sees her family looking the worse for wear. Poppa Bernard (William Sadler) has the deep violet claw marks of a rumpus fetish slam session while momma Joanna (Deborah Rush) is geared up in ocular pirate attire after (assumingly) having an eye scratched out by her mid-exorcism daughter. Like coming to after a three day bender of a rolling blackout, there are scores to settle and wronged people to make amends with.

In Ava’s case, the pieces to be picked up, sorted through and rearranged now that the demon has left her fleshy vessel for clearer, less holy skies are of a vaguely sinister type. Friends stop calling (“You kinda acted like a crazy bitch when you were possessed”), bills piled up, her PO-ed employers weren’t notified of her “sick leave” and now even lingering assault charges lurk in the shadows. Also, Ava’s goldfish died. Rather than face a slew of felony charges – ranging from indecent exposure to criminal battery – Ava agrees to attend an unconventional 12-step program for former possessed individuals aptly called Spirit Possessions Anonymous.

Her attempts to connect the dots of her possession fulfills both Ava’s personal curiosities and the requirements of her state-mandidated 12-step program. Director, producer and writer Jordan Galland exploits the sleuthing aspects of the film to suss out a somewhat ill-defined, old-timey detective aspect to the film, allowing the proceedings to temporarily percolate with a rare genre-mashing synthesis of horror and noir that holds much promise.

Regretfully with all these eggs in one basket, Ava’s Possessions begins to hobble. As if clubfooted, the film takes a sharp turn towards brutal mediocrity in its attempt to collage together too many genres as a parallel string of poorly developed characters with wishy-washy motivations become focal points of the mystery Galland’s so busy trying to brew up. Before long, a numbing final act has Ava veering violently off the cliffs of full-blown stupidity. That Ava’s Possessions is eventually sucked into an event horizon of glib self-satification and narrative inconsequential fluff – with a resolution that’s almost as rank and implausible as last year’s atrocious Horns – is a damn shame; another good premise seemingly wasted with scuffled execution.

Galland states that his motivation to make the film came from an encounter with a passage in “Herzog on Herzog” that loosely read: “There is no excuse not to make the movie you want to make.” For a set-up as creative and effective as Galland’s is, Ava’s Possessions is clearly an inspired concept, that dream project cooked up by a idea-hungry director. Nevertheless, Galland winds up possessed by the belief that he cram as much mismatched materials as he deems fit and it’ll still land butter side up. The law of averages says otherwise.