"Coherence" (DT 13/02/15)

Coherence ***

Dir: James Ward Byrkit. Starring: Emily Foxler, Maury Sterling, Nicholas Brendon, Lorene Scafaria, Elizabeth Gracen, Hugo Armstrong. 15 cert, 89 min

Movie rule-of-thumb advises you think long and hard before RSVP-ing to any dinner party invite: chances are, no-one’s going to get through to the Matchmakers entirely unscathed. Luis Buñuel’s prankish The Discreet Charm of the Bourgeoisie repeatedly denied its guests even a starter; those invited to 1995’s The Last Supper found themselves being carved up. To this infernal social calendar, we can now add James Ward Byrkit’s nifty US indie Coherence, which gathers an octet of comfortable Caucasian thirtysomethings at one brightly appointed home, before skilfully undermining everybody’s certainties.

Early, ominous small talk concerns the comet set to pass overhead this particular night. Something’s in the air, all right: one invitee, Em (Emily Foxler), has already seen her phone cut out and its screen shatter en route, a prologue that sets the tone for a film of sudden blackouts and crack-ups. Byrkit’s big reveal comes once the comet’s passed and the lights have been restored: a tentative sally to the one neighbouring house with power brings the party face-to-face with other versions of themselves, no less curious to know what’s going on.

As reality fractures, a rather obviously self-contained production begins to attain philosophical dimensions. Coherence chimes with recent Saramago adaptations The Double and Enemy in pitting doppelganger against doppelganger, yet Byrkit resists those films’ overt stylisation, instead keeping everything within the realms of (relative) plausibility. Quantum physics here comes to rub up against basic table etiquette: one explanation offered for the general disorientation is that everybody’s thrown back too much red wine. Been there.

Part of Coherence’s fun lies in the suggestion this low-key invasion of the body snatchers might just be an elaborate after-dinner game; as the characters reach for pen and paper, or the Yahtzee dice, or a Schrodinger’s cat analogy, their bafflements and breakthroughs become our own. Its success may depend on how alert you’re feeling, but for once you can’t complain that a movie hasn’t given your synapses a thorough workout: as with 2005’s time-travel curio Primer and 2007’s Spanish mathfest Fermat’s Room, this involving puzzle-piece might usefully be prescribed as a means of holding Alzheimer’s at bay.

Coherence opens in selected cinemas from today, ahead of its DVD release on Monday.