The quiet atmosphere at a small beach resort is rattled by the suspicion of an unheard-of shark invasion, which alarms the locals. 14-year-old Rosina, the middle child of three siblings, has no friends, and her exchanges with the world only consist of monosyllables and the occasional short phrase. She thinks she saw something in the water, but no one seems to be paying much attention to her. Her family is more concerned about their tight economic situation, work and the approaching summer season. When her father recruits her to do maintenance work at some summer houses around town, she meets Joselo, a slightly older fisherman. To get his attention, she comes up with a convoluted, poorly planned strategy, going about it stealthily and menacingly, as if inspired by the mysterious predators.