Vincent, a teenage humpback whale, is the orphaned son of the last Whale Singer, whose magical song once protected the oceans. Burdened by the loss of his parents, Vincent doubts his own abilities. When the monstrous Leviathan escapes from a melting iceberg, threatening all marine life with its poisonous ink, Vincent must find his own song to stop the threat. But overwhelmed by self-doubt, he instead embarks on a perilous journey to the deepest point of the sea to bring his parents back from the mythical Star Pool, hoping his father can defeat the Leviathan in his place.