On New Year's holidays, Mariana (21) and Rodrigo (30) drive to the coast where he has to sell a property. There, they find Karina (7), late at night and in the middle of nowhere. She tells them she has run away from home because her uncle touches her. They decide to stay the night and try to find help in the morning. But by dawn, the girl is gone but hundreds of poisonous sea snakes swim out of the unusually cold water.