Keisuke's next opponent in Kanagawa's Four Lines of Defense is the leader of Team Spiral, Ryuji "Zero" Ikeda. Ikeda believes in his "Zero Theory", where the driver thinks of nothing except being one with the car to create the ultimate racer. Quite similar to Ryosuke's Fastest Racer Theory, Ryosuke also notices a few flaws in Ikeda's theory. A flaw that would arise as the wet conditions create a fog battle.