Sharks and confined spaces are both big fears for much of the population - so combine the two and you've got what looks like a genuinely terrifying film.
47 Metres Down is the latest film in the shark attack horror canon that started with Spielberg's Jaws back in 1975 and continued most recently with last year's so-so The Shallows.
47 Metres Down at least looks more involving than that film because the sharks in question don't display an unconvincing preoccupation with Blake Lively.
Judging by the trailer, released this week, the plot seems paper-thin but action-packed: Mandy Moore and Claire Holt play a couple of holidaying girlfriends who decide to take the plunge and go cage diving with sharks.
Once they're in the water, they discover the sharks are much bigger and meaner than they'd anticipated - and they'd very much like to get back on the boat, please.
That's when the fun starts. The cable dangling their cage in the water snaps, sending them trapped and plummeting 47 metres to the ocean floor below as hungry sharks circle.
The film was originally to be a straight-to-DVD release, but perhaps buoyed by the success of The Shallows, it'll now be shown in cinemas in the US in June.
No word yet on a New Zealand release date.