Dark Waters

A remote, storm-swept island, a population of evolutionary throwbacks, a forbidding Medieval monastery, a strange religious order, ancient, undying evil. After the death of her father, a beautiful Londoner travels to a desolate island to investigate the dead man's bequest of a large sum of money to be paid annually to the reclusive nuns of a local convent. Given little information from the secretive sisterhood or their blind Mother Superior, Elizabeth strikes out on her own with the aid of a helpful novice and discovers the convent serves as a prison for an ancient aquatic demon whose awful wrath is held at bay only so long as the fragments of a stone amulet bearing the monster's horrific likeness are kept separated. (official distributor synopsis)