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.

Having temporarily stalled Viral and Thymilph in the last skirmish, the Team Gurren and their newly arrived allies join forces as "Team Dai-Gurren" and launch a decisive strike against the regrouping Gunmen force.

At last, Simon and Nia are reunited, and by combining the power of its members, Team Dai-Gurren creates the galaxy-sized Tengen Toppa Gurren-Lagann, and engage the Anti-Spiral threat in a decisive battle to determine the fate of the universe.