Eiji Hino is a man who has no dreams, no job, and no family. When animal-like monsters called Greeed awaken after their 800 year slumber to attack humans and feed off of their desire, a bird-type Greeed called Anku gives Eiji a belt and three Medals to fight the Greeed so he can become the predestined Multi King. This allows Eiji to become Kamen Rider OOO. The mysterious Kougami Foundation approaches him and begins assisting him in his fight against the Greeed, but their true motives are not clear. When Eiji fights for the first time, he starts to realize what it means "to be alive".