As the Tenjin Archery Tournament approaches, Ai and Mai Amatsu continue their training to protect the mischievous descendant of Tenjin, Onimaro. During the festival's purification rituals, the demon Sekimouki launches a surprise attack, sealing the twins' powers and attempting to abduct Onimaro. Despite the onslaught, Ai and Mai synchronize their spirits to unleash the powerful Thunder Dance, repelling the demon beast and reaffirming their duty as Tenjin Watchers.