Kazuo Yamashita is an ordinary fifty-six year old man who one day is summoned by the chairman of his company and hired as a manager of a gladiator. He learns that these hired gladiators engage in battles called "Kengan Matches" to protect the corporate rights of the businesses they represent. Kazuo Yamashita is assigned to manage a mysterious Kengan fighter named Ohma Tokita. Both men join the "Kengan Zetsumei Tournament" with the hope of winning the spot as chairman of the Kengan Organization.