Blake Lively faces off against a shark in the thrilling new film The Shallows.

Starring Blake Lively, information pills The Shallows is a low-budget thriller that heartily embraces its simple concept. Lively stars as Nancy, a surfer, who becomes stranded on a rock 200 yards away from the beach while a shark closes in. Director Jaume Collet-Serra, who previously helmed the underrated House of Wax (2005) and the commendable Non-Stop (2014), uses feature’s premise effectively and efficiently to create a highly watchable and commendable thriller.

When the feature starts, a young boy finds a GoPro camera on the shoreline. He watches the footage. In the tape, he witnesses a surfer getting attacked by a shark. Like in Jaws or Jurassic Park (two other features about menacing creatures), this first sequence hints at the horror to come.

The next scene shows Nancy travelling to the beach with a man who offered her a ride. The sequence is packed with exposition but sets the story up nicely. Nancy is visiting a Mexican beach that her late mother told her about (it was “their” beach, she says). When Nancy arrives, she doesn’t know the name of the beach but she knows how thrilling it is.

Nancy makes some new friends and spends her afternoon surfing the beautiful waves. When she’s left alone though, a shark attack leaves her stranded on a barely above-water rock and pursued by the creature.

By focusing the main character, writer Anthony Jaswinski manages to create enough of a personality for Nancy to earn the audience’s sympathies. Aside from two brief scenes, Nancy spends most of the film’s running time at the beach. But Jaswinski has done enough in the transportation scene and in a brief video chat she conducts with her father and sister to set up the character’s background.

Nancy is a medical school student who wants to leave her studies behind but luckily for her, those same studies have helped prepare her for the shark’s attack. Because of that, the character’s ability to prevent blood loss feels realistic and natural.

Although the shark’s presence is always felt, the filmmakers create suspense even when the creature is offscreen for most of the story. In fact (and this may be for creative or budgetary reasons), the filmmakers often steer clear of depicting the actual attacks onscreen. Instead, we witness the tragic results of an attack. We watch as characters quickly disappear into the water. Until the very end, the filmmakers don’t show what the shark is truly capable of.

Instead, they realize that less is more.

As a whole, the thriller wouldn’t work at all without a lead actress who can tell a story with her facial expressions. Lively’s performance shows she’s up to the challenge. Even in the early truck ride scene, the camera lens focuses in on Lively’s face– letting the actress showcase her emotional state with her expressions alone. When the character is eventually stranded, the actress has to constantly reveal her emotional state without speaking.

Nancy may have the companionship of a solitary seagull but that’s it for much of the feature’s running time. Because of that and a dozen other filmmaking decisions, The Shallows succeeds as a tense thriller that will make audiences nervous before they even step into the ocean.