The decisive battle between Build Divers and the Second Coalition of Volunteers begins, while Riku and Momo attempt to sneak by the enemy's defenses to reach Sarah, the others confront the enemy forces. In the occasion, Tigerwolf and Shahryar face off in combat, and after the victor is decided, they agree to help the Build Divers together, but they are easily defeated by Kyoya, who challenges Riku for a duel.