Cosmina is a police officer in the Romanian coastal town of Mangalia. When a body is discovered on the shore, Cosmina and her partner, Liviu, are assigned to the case. The identity of the victim is soon discovered to be a local construction worker with a distinctive seahorse tattoo on his collarbone.
As the investigation progresses, Cosmina and Liviu discover the victim is linked to the disappearance of a teen girl, Ioana. Liviu wants to step back from the investigation, but as more bodies come to surface, Cosmina is convinced that the series of deaths have been caused by a mysterious aquatic creature. Cosmina is determined to find out the truth behind the supernatural creature and Ioana’s disappearance. While trying to uncover this, she meets a strange land owner with a bandaged head, Ionut who claims to have brought a dog back to life with love, a foster home nurse with a dark past. She then discovers a child trafficking network and the secrets behind the dark foster home.