Living underground in Giha Village, Simon and Kamina dream of a life on the surface. When their home is invaded from above, it is up to them to activate the mysterious mecha Lagann and save their village.

Now that they've made it to the surface, Simon and Kamina must join together with Yoko and her village to defeat the Beastmen pursuing them.

Team Dai-Gurren falls into a trap set by the third member of the Four Divine Generals, Guame. The Team is taken captive and stored underground to await execution. While digging an escape path, Simon finally understands Kamina's last words to him and after having a discussion with Guame, Nia finds out the reason why she was thrown away.