Beyond the human realm lies a mystical world inhabited by beings who control the tides and the changing of the seasons. One such being, a sixteen-year-old girl named Chun, undergoes a rite of passage by traveling to the human world in the form of a red dolphin. During a violent storm, she becomes entangled in a fishing net and is saved by a human boy who drowns in the process.

Consumed by guilt and determined to return his soul to the human world, Chun makes a deal with the sinister Soul Keeper, trading half of her lifespan to revive the boy as a small fish named Kun. As Kun grows into a colossal whale, his presence disrupts the natural balance of Chun’s world, triggering catastrophic floods and disasters. To save both Kun and her people, Chun—aided by her devoted friend Qiu—must navigate a heartbreaking journey of sacrifice, love, and the cyclical nature of life and death.