Tengen Toppa Gurren Lagann is a mecha comedy anime by Hiroyuki Imaishi and studio Gainax. In an underground city, a group of kids find a strange glowing object during excavation. They form the Gurren Brigade to break through the cave's ceiling in an attempt to reach the surface world.
Tengen Toppa Gurren Lagann is a 27 episode anime TV series directed by Hiroyuki Imaishi and produced by Studio GAINAX. In addition, it has an ongoing manga adaptation, a light novel, a spin-off manga, a game, and 2 anime films that retell the story from the original anime.
The show takes place in a fictional future where the Earth is ruled by the "Spiral King" and all humans must live below the ground. Protagonists Simon and Kamina break through into the surface and fight the king.
For more information, see the Gurren Lagann wiki or the wikipedia page