We follow the story of Nancy (Blake Lively), who recently dropped out of medical school and has travelled all the way to the mysterious, well hidden and unnamed beach her mother went to when she found out she was pregnant. While surfing at this beach, Nancy is attacked by a Great White Shark, and she's forced onto a rock for safety. With just 200 feet between her and the shore, surviving should be an easy task... except for the fact that the shark isn't giving up anytime soon. It's a game of survival, and with very little options of what to do, winning this game isn't looking very likely.
For the most part, this film is just Blake Lively alone on a rock, along with an adorable show-stealing seagull who I had a bigger emotional investment in. But aside from that extremely loveable bird, and the uh killer shark, it's really just her. She has to carry this entire movie, and that's a big task. She's not going to be winning any Oscars for her role, but in my opinion, she did a solid job. She's a strong character with a handy set of skills (she'd totally be dead if she hadn't gone to med school) and Lively really sells her.
To sum up, The Shallows is a well directed and incredibly suspenseful thriller that's both tense and difficult to watch. Blake Lively gives one of her best performances to date, and while the third act does get a bit ridiculous, it doesn't take away from the effectiveness of the rest of the film.