Many years ago, humans and demons lived in harmony. But that unity ended when demons started attacking humans and plotted a mission to unleash Gyumao—an evil demon imprisoned for thousands of years. Now, Genjo Sanzo, a rogue priest, must team up with three demons—Sha Gojyo, Son Goku, and Cho Hakkai—and embark on a perilous journey to the west to stop these demons from resurrecting Gyumao and restore the balance between humans and demons on Earth.

With the seniors having graduated from high school, the determined swimmers eagerly take on their futures with a dream to fulfill. Now attending Hidaka University in Tokyo, Haruka Nanase unexpectedly runs into Shiina Asahi, an old teammate and friend from his middle school days. Consequently, the troubling memories regarding his middle school swim team resurface, as it was a time when Haruka's views on swimming became negative and led him to quit the team. Haruka later reconnects with his other middle school classmates; all except for Ikuya Kirishima, who still resents Haruka for quitting the team, resulting in its disbandment. Aware of the issues between them, Haruka resolves to improve his friendship with Ikuya. However, he quickly realizes that making amends with an old friend isn't his only obstacle. Facing the reality and challenges of encountering higher calibre swimmers, Haruka must work hard to establish himself if he dreams of competing on an international level. [Written by MAL Rewrite]

Rin Matsuoka’s childhood friend, Sousuke Yamazaki, has recently transferred to Samezuka Academy. Upon their reunion, the two reminisce about their childhood days and reaffirm their wish to swim together. Now with Rin, Sousuke, Captain Mikoshiba’s younger brother Momotarou Mikoshiba, and hard-working Aiichirou Nitori, the Samezuka relay team is formed, and their friendship deepens. However, as tournaments, races, and training go on, the reason for Sousuke’s sudden return begins to trouble him and affect his swimming. Noticing Sousuke’s change, Rin pushes to uncover what is holding him back. [Written by MAL Rewrite]

In an old mythical world, there reside spirit-like beings who oversee the natural order of the mortal realm. One of them, a young girl named Chun, has just come of age and must undergo her rite of passage by experiencing the human world for herself. While there, she gets caught in a fishing net during a storm and is rescued by a human boy.

However, the boy ends up drowning during the incident, and Chun returns to her realm full of guilt. Afterwards, she meets the Soul Keeper and decides to revive the boy in exchange for a part of her lifespan. Little does she know, meddling with the natural order of the world has severe consequences.

Da Yu Hai Tang is a story about sacrifice and redemption as Chun comes to terms with the limitations of her powers and deals with death, love, and her own emotions. She must decide if she will sacrifice everything to save the human boy or forsake her moral obligation for the order of the world.