The film takes place on the Greek Island of Spetses, where widowed Greek-History Professor Thomas Bradley is about to lose his research grant studying ancient love spells. He knows he is close to a major academic breakthrough and desperately wants to continue his research. Thomas is given one last chance to continue his work on a Greek island, at the home of the supportive Oxford don, Professor Coulter. Joined by his 12 year-old daughter, Serena, Thomas departs to the Greece island looking for the inspiration he needs to finish his thesis. Serena knows that what her father needs most of all is to find love again after the loss of his wife. Initially, Serena tries her hand at matchmaking with the local women on the island, who are less than impressed by the awkward and clumsy Thomas. Very much in tune to the ancient spirits herself, Serena meets Nereid a beautiful mermaid. However, menace is present in the form of the evil Captain Mavros, an island fisherman intent on killing Nereid and getting his claws on her priceless jewel-encrusted tail. Serena realizes that she has finally found the ideal match for her father and employs her father's ancient Greek love spells to make them fall in love. Eventually Nereid sacrifices her immortality to become a mortal human being, joining Thomas and Serena back in Oxford where Thomas's thesis is received in triumph.
—Wikipedia