On the coast of Cork, Syracuse is a divorced fisherman who has stopped drinking. His precocious daughter Annie has failing kidneys. One day, he finds a nearly-drowned young woman in his net; she calls herself Ondine and wants no one to see her. He puts her up in an isolated cottage that was his mother's. Annie discovers Ondine's presence and believes she is a selkie, a seal that turns human while on land. Syracuse is afraid to hope again.

Martha, an emotionally fragile mother, who moves to a remote Irish village with her husband Tomas following the tragic death of their baby daughter. Whilst there, the couple decide to take in a disturbed and orphaned autistic girl called Daisy. Uncommunicative and greatly scarred by the violent death of her parents, Daisy gradually warms to her new surroundings. But, as a series of strange occurrences begin to be linked to the little girl, Martha and Tomas begin to hear rumors from the locals that Daisy might be something far more malevolent than she seems. Written by Marisa_Gabriella