Isaku Honjo is a cold-blooded prosecutor who will go as far as fabricating evidence to bring criminals to justice. One day, he loses his life in a tragic accident alongside his wife and daughter, only to descend into Hell. There, a "Millennium Festival" is being held by demons. The demon Bune takes notice of Isaku and approaches him with a contract to become a "Devil's Advocate" in the event. If he participates in the festival and obtains the legendary Ring of Solomon, any wish can be granted—including the resurrection of Isaku and his family. Accepting the contract, Isaku plunges into the Millennium Festival as Bune's proxy, brandishing the sword of judgment against the demons. Can he ultimately claim the Ring of Solomon? This is the ultimate dark fantasy, where a man who once wielded sharp wit as a prosecutor now passes judgment upon the demonic realm.