One year earlier, Yoko starts working as a schoolteacher on an island until she learns of the situation at Teppelin and returns to break Simon free. Once again reunited, Simon and the members of Team Dai-Gurren launch themselves into space to protect the Arc-Gurren from the enemy forces, now accompanied by Viral as co-pilot of the Gurren-Lagann.
Trying to do her part in Team Dai-Gurren, Nia decides to become a cook, but just before the crew have a taste of her dishes, Cytomander, the fourth member of the Divine Generals, launches an aerial attack on the Dai-Gurren. Simon leads the counter-attack on the Gurren-Lagann, this time accompanied by Yoko, who replaces a sick Rossiu.
Team Dai-Gurren are now on their way to Beastmen's capital city, Teppelin but there's a vast ocean in their way. The only way for them to get across is for the Dai-Gurren to be modified, so while they wait everyone goes to chill out at the beach. Once preparations are complete, the Great Gurren Brigade begins their cruise, but there's an ambush waiting for 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.
Nia true identity is revealed, as she flaunts her authority to get rid of another one of the Four Divine Generals, Adiane. The members of the Great Gurren Brigade are now suspicious of Nia and her true intentions, but she is only concerned about the depressed Simon. Adiane later returns to finish them all off, with Lordgenome's blessing.
Team Dai-Gurren managed to take control of the enemy fortress, but is still mourning the death of one of their own, especially Simon. After falling off a cliff, he notices a Gunman throw a capsule into a deep valley. Simon inspects it and finds he is able to open it with the same drill key he uses to pilot Lagann, and inside is a young human girl named Nia, but their introduction is cut short when an enemy Gunman appears.