Ren Yu, a merman, is swimming in the ocean when Long Jie suddenly appears to him in the water.  Suddenly, Ren Yu finds himself on land saving Long Jie's life, but without his tail.  Without his tail and unable to return to the ocean, Ren Yu follows Long Jie home. 

Ren Yu seeks out ways to improve Long Jie's happiness, starting by helping him make amends with a friend.