Haein, a typical high school student from South Korea, one day decides to visit a swimming pool. However, she gets swallowed up by a mysterious whirlpool and loses consciousness. When she wakes up, she finds herself deep inside the ocean, where she meets Ellime. To her surprise, he claims to be her father. Haein soon discovers that she was born to the Spirit King and a half-elf mother. Will she be able to navigate through this new world she's been thrown into?