After losing both parents in a fatal plane crash, teenager Ryuuichi Kashima must adjust to his new life as the guardian of his younger brother Kotarou. Although Ryuuichi is able to maintain a friendly and kindhearted demeanor, Kotarou is a reserved toddler still too young to understand the reality of the situation. At their parents' funeral, they are approached by Youko Morinomiya, the stern chairman of an elite academy, who decides to take them under her care. However, there is one condition Ryuuichi must fulfill in exchange for a roof over their heads and enrolment in the school—he must become the school's babysitter. In an effort to support the female teachers at the academy, a babysitter's club was established to look after their infant children; unfortunately, the club is severely short-staffed, so now not only is Ryuuichi responsible for his little brother, but also a handful of toddlers who possess dynamic personalities.

A boy, Tsuwabaki Daiya found a black fire in an ocean when he and his father were in a small boat. A big monster came out of the fire, and the father and the crews were disappeared into the sea. When he was about to become the next victim, a large mecka dragon appeared and saved him. 5 years later since then, Daiya becomes a junior high school student. A big monster reappear, and he meets the mecha dragon,Daiku Maryu. The head of the dragon separates from the body, and it turns into the body of a super robot, Gaiking. He gets in Gaiking, fights against the monster, and beats it. He learns that there is an enemy that plots to conquer the world, and he leaves for another world, Darius, to stop the plot. (Source: AnimeNfo)

Specials included with the Blu-ray/DVD release of Gabriel DropOut.

2nd season of Gakkatsu!.