Kuroo Hazama, also known as "Black Jack," is a legend in the medical world. Famous for being one of the best, as well as not having a license, Hazama and his assistant Pinoko save countless lives that other doctors cannot... for a price; an exorbitant price, in fact, which causes many to view the genius as greedy and heartless. Despite these claims, however, none can deny his skill and the lengths that he will go to treat his patients. This dark medical drama tells the story of the ominous and mysterious world of underground medicine as Black Jack risks his life to cure some of the most bizarre diseases imaginable, even if it means breaking every law in the process. [Written by MAL Rewrite]

After the death of his parents, a young Mirai Kakehashi is left in the care of his abusive relatives. Since then, he has become gloomy and depressed, leading him to attempt suicide on the evening of his middle school graduation. Mirai, however, is saved by a pure white girl named Nasse who introduces herself as a guardian angel wishing to give him happiness—by granting him supernatural powers and a chance to become the new God. In order to earn the position, he must defeat 12 other "God Candidates" within 999 days. Soon, Mirai begins a struggle to survive as a terrifying battle royale erupts between himself and the candidates looking to obtain the most power in the world.

In the senior high school division of Shuchiin Academy, the student council president and vice president, Miyuki Shirogane and Kaguya Shinomiya, appear to be the perfect couple. Kaguya is the daughter of a wealthy conglomerate family, and Miyuki is the top student at the school and well-known across the prefecture. Although they like each other, they are too proud to confess their love, coming up with many schemes to make the other confess.

Special episode serving as the conclusion to the anime series.