Mavka is a dangerous nymph of the forest lake that lure people into its depths for the mermaids to feed on their energy. When she meets Lukian, a biology whizz, Mavka falls in love disrupting the natural order.
The lives of six girls belong to different worlds although connected to each other through a doll called Molly, whose existence dates back to 1976, when she appeared among the rubble of the great fire of the San Carlos orphanage, in northern Spain.