Simon and Nia are reunited. Team Dai-Gurren uses their combined spiral power to merge everyone together and create the galaxy-sized Tengen Toppa Gurren-Lagann, engaging the Anti-Spirals in a decisive battle for the fate of the universe.

In a medieval Europe setting, Simon, Kamina and Viral infiltrate a castle where Nia is held captive by a Grand Zamboa-like enemy. Viral's wife and Yoko also make appearances.