Sara (Itziar Martinez) comes to friends, they are going to throw a party, a good start to a wonderful evening, everything is going well, here you can relax in a circle of people you know well. Sarah should rest, have fun and not think about work, get away from the problems at least not for long, but with her character, even here it will be difficult, because in life she is not so smooth as she wanted. In the evening, a barbecue is planned, here the girl is waiting for new acquaintances, and then there will be an evening of parties and dances, Zak invites everyone. But the mood is overshadowed by a strange guy who warns Sarah about the fact that here she is in for big trouble and she should run away from here. And then strange things began, and unexpectedly the girl began to find herself in the pool, time after time, as if an unknown force was carrying her here. Devilry, someone wants to drown her, dreams at night and threatens to take it with you. Nereus is a film about an ancient monster who settled in a pool in the courtyard of a residential complex and is eager to get prey, and he has already chosen a victim, this fragile girl came to his taste and he would not miss it. Whether to free Sarah from the clutches of a terrible creature, which is also not visible in the water, it merges with the depths of the water because it is a part of her, her body.