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.
A Greek History Professor & his daughter travel to a Greek Island for one last chance to finish his thesis on ancient love spells before he loses his research grant. His daughter attempts to match her father with the local women without success until she meets a beautiful Mermaid with whose help the Professor might finally find true love for himself.