I am a sucker for a fun killer-shark movie (no, Sharknado and its purposefully bad brood of sequels do not count), and I enjoyed Johannes Roberts’ 47 Meters Down even more than last summer’s taut The Shallows. 

The premise is simple: Two sisters—the boring older one, Lisa (Mandy Moore), is nursing a breakup, and her wild little sis, Kate (Claire Holt), wants to help—are vacationing in Mexico. They meet two local boys who encourage them to go swimming with sharks, sort of. A probably unlicensed Capt. Taylor (an appropriately scruffy Matthew Modine) takes tourists down about five meters in a shark cage for 100 bucks a pop. Unfortunately, his not-up-to-code setup breaks while Lisa and Kate are under, dropping them 47 meters to the bottom of the ocean, where they are trapped, running out of air and surrounded by bloodthirsty, 20-plus-foot great whites. 

It’s a tailor-made primal nightmare, and Roberts milks it for all of its tension. Moore and Holt do the heavy lifting, making Lisa and Kate feel like endangered siblings, not just pretty cardboard victims. The underwater photography and CGI meld into a natural, terrifying tableau. Sure, 47 Meters Down is gimmicky—it’s like an underwater John Carpenter siege flick. Roberts, who is currently directing the long-awaited Strangers sequel, has expressed admiration for Carpenter, and keeps his flick effectively lean, like his hungry, constantly moving predators.