Even as he tries to keep the student council president out of trouble, Vice President Chiga-kun finds himself being drawn to the president's strength and power. Chiga-kun wonders how he, being such an intelligent individual, can be so unwillingly taken with a boy who is so country and simple...

Fourth season of .

During the An Lushan Rebellion of the Tang Dynasty, monsters are everywhere and the people were destitute in the Central Plains. Li Haobai started from the Bashu and wanted to go to the front line to make a meritorious deed. On the way he was swallowed by the monster. By coincidence, Li Haobai and the guardian of the dragon’s veins merged with each other to obtain the power of the black dragon. And he has since been involved in the struggle of various forces.

Surrounded by a forest and a gated entrance, the Grace Field House is inhabited by orphans happily living together as one big family, looked after by their "Mama," Isabella. Although they are required to take tests daily, the children are free to spend their time as they see fit, usually playing outside, as long as they do not venture too far from the orphanage—a rule they are expected to follow no matter what. However, all good times must come to an end, as every few months, a child is adopted and sent to live with their new family, never to be heard from again. However, the three oldest siblings have their suspicions about what is actually happening at the orphanage, and they are about to discover the cruel fate that awaits the children living at Grace Field, including the twisted nature of their beloved Mama. [Written by MAL Rewrite]