Greek underworld god Thanatos assumes priestess Calliope marries him for immortality and treats her coldly. When Calliope falls terminally ill, he waits for her to beg for eternal life. Instead, she accepts death and her soul dissolves into the cosmos, proving she gave up sacred longevity only to ease his loneliness. Shaken by her memories, Thanatos defies underworld laws and desperately chases her scattered soul fragments.