AllMovie

Legends say that eating the flesh of a mermaid will grant a human immortality. Yuta knew nothing of this legend when he accidentally did just that 500 years ago, but now he knows that the immortality that comes with this process is not a blessing but a curse. Wandering in search of another mermaid to release him from his earthly imprisonment for all this time, he has nearly given up hope when at last he discovers a group of mermaids, but finds that they have a human girl held captive with them. They have raised her from childhood and plan on sacrificing her and eating her flesh, as this is how mermaids stay youthful. Yuta immediately jumps to the girl's rescue and slays them, but it is too late: the girl has already eaten a piece of the mermaid's flesh. Now, Yuta has a traveling companion, the young and naïve Mana, who has been trapped by the mermaids all her life and now finds amazement and interest in the most everyday phenomena. Together, they wander in search of the secret to unlocking the curse of their immortality.