Ryo Takatsuki learns that his missing right arm is actually an ARMS nanomachine implant from secret genetic experiments, and alongside fellow test subjects Kei Karuma, Takeshi Tomoe, and Hayato Shingu, he battles the creators of the technology, the Egrigori, to rescue his kidnapped girlfriend Katsumi Akagi.

Project Arms ran for 2 seasons. No new episodes are scheduled.