Arthur C Clarke once said that there are two possibilities. Either we are alone in the universe or we are not: both are terrifying. But the funny thing in this sci-fi thriller – about parallel universes rather than alien lifeforms – is quite how unterrified, or even awestruck, these four Seattle housemates are when a mirror in their attic turns out to be a portal to a “multiverse” of alternate realities. They barely pause to register the uncanny weirdness of bumping into versions of themselves. Nope, they move straight on to the important matter of making money.

What they discover is that the parallel universes (or “alts” as they call them) tick along much like our world: same major events but with slight divergences, particularly in industries like art and tech. “Look, Mona Lisa’s hair is short!” exclaims Leena (Georgia King) flicking through an art book in an alt. (It’s perhaps best not to dwell on the logical impossibilities.)

So, this mediocre bunch start stealing ideas from the alts and passing them off as their own – a shortcut to greatness. Ruthlessly ambitious Noel (Martin Wallström), fancying some Elon Musk-style world tech domination, pops behind the mirror to stock up on innovations by actual geniuses. Leena, a struggling artist, appropriates work by a leading painter in an alt and becomes an art world sensation, only to experience a wave of self-loathing.

The ideas here present an interesting variation of traditional sci-fi themes from movies such as Groundhog Day, Primer and Flatliners. So it’s a shame that the script goes down the conventional thriller route: success tests the group’s friendships, and there are a couple of showdowns involving guns (neatly solved by the ease of disposing of bodies in other universes). It’s watchable, but don’t expect your mind to be blown – more gently prodded.

• Parallel is released on 14 June on digital platforms.