Seven years have passed after the battle of Teppelin... Humans have since reclaimed the surface of the earth and enjoy an unprecedented period of peace and prosperity. However, humanity's increasing population growth triggers the sudden emergence of an unknown, powerful enemy. The fearsome, manipulative power of the mysterious Anti-Spiral proves too overwhelming for humans to even fight back. When everyone becomes desperate and loses hope, Team Dai-Gurren members reunite to stand up once again!

Simon and Kamina live in an underground city monitored by the village chief. When Simon stumbles upon an artifact and beastmen invade from the surface, Simon and Kamina rebel against them.

After arguing about whose fashion sense is better, Takaharu and Kinji go outside with their costumes to be judged by the public. Expectedly, they are laughed at due to their outrageous costumes. They then notice a dark aura surrounding several stones, which Kinji depicts as Hyakki Yakou, an event in summer where a hundred Youkai would revive and destroy the town at night.