Who would have thought that surfing on your own on a strange beach in a foreign land in shark infested waters could possibly go wrong? A medical student (Blake Lively) thinking of giving up her studies is on vacation in Mexico (the film was actually filmed in Australia) and heads off to a secluded beach that has a personal connection for her. After the only other two local surfers leave she decides to stay in the water, and quickly discovers who is top of the food chain in the area.