ZENONZARD, an electrifying card battle game, has taken the world by storm in the futuristic year 20XX. Humans, known as "Concodes," unite with advanced AI, referred to as "Codeman," to become partners and rival teams in the prestigious world championships, THE ZENON. In the midst of excitement, an enigmatic woman introduces herself as Eilietta Lash and challenges ordinary high school student Souta Azuma to a battle. Eilietta unveils herself as a Codeman and invites Souta to team up with her to compete in THE ZENON. Despite some reluctance, Souta agrees to join forces with Eilietta. Their first formidable rivals happen to be Shion Saionji, who happens to attend Souta's school, and her Codeman buddy, the famous Ash Claude.