On the other side of the Nai River is the underworld where darkness reigns all year round. The underworld uses ghost messengers to maintain the balance of life and death in the three realms... and the ghost messenger who goes to the human world to collect spirits is the Black and White Warriors. The Black and White Warriors are the last-place combination - Xiao Hei and Xiao Bai. After experiencing the Hundred Ghosts Sealing incident, the relationship between the two becomes ambiguous, and Xiao Bai's life story gradually comes to light...