第 15 集: Oni-Hige 組織一場致命的紅寶石遊戲，以保護 Otokojuku 免受 Great Kanto Student Alliance 侵害。

15

Oni-Hige is put in charge of the school while Principal Edajima goes to Kansai. The instructors see this as an opportunity to make some money to replace the bonuses they have not received. To raise money, Oni-Hige resurrects the School Festival which was banned for 10 years due to many student fatalities. Meanwhile Akashi reveals that the aggressive Kanto Great Student Alliance plans to make Otokojuku the 100th school under their control. Akashi leaves it to Momotaro and the First Years to resolve. A thousand Kanto Great Student Alliance students arrive to take over the school, but Morita, Captain of the Guard says he needs only 30 men to make them surrender. As the battle is about to start, Oni-Hige interrupts and suggests a game of ruby instead, to protect the other visitors and make more money. Oni-Hige poisons the players who must reach the antidote at the other players' end with the steel ball containing a key within 20 minutes or die. The game begins. (Source: Wikipedia)