“Ondine” is the enchanting story of Syracuse (Farrell), a lonely fisherman who one day pulls a beautiful woman named Ondine (Bachleda) out of the sea in his nets. His young daughter Annie is convinced that she is a “selkie” —a creature from Irish folklore much like a mermaid. Syracuse has his doubts, but as Ondine brings some luck and joy to his otherwise downcast life, he starts to come around as well. “Ondine” deftly blends romance and fantasy with the realism of modern life in an Irish seaside town.