The brothers' routine is shattered when a hot chick (Yoko) who claims to be from the surface plummets into their world while doing battle with a massive robot. In the heat of the conflict, Kamina and Simon escape with Yoko to the surface. When the heat dies down, the two decide to stay rather than return to their home, and help a ragtag team of humans do battle with the machines and the monstrous "Beastmen" who seek to destroy them.
If Gurren Lagann's plot is silly and predictable, the show succeeds in its sense of humor and ass-kicking characters. The loudmouth Kamina has the monopoly on the show's zingy one-liners, screaming what feels like a million jokes a minute at top volume. His words of wisdom "believe in the me who believes in you" have a ring of truth to them and actually help inspire the villagers in their struggle against the gigantic mechas that threaten to devastate their already-precarious existence.
Even the timid Simon is able to rise to the occasion in grand fashion. He's no hero (in fact, he freely confesses his terror in almost every scene, much to Kamina's chagrin), but he'll go on keeping people safe until someone else volunteers to do it for him.
The show's real heart is in the relationship between the brothers and their shared blue-collar spirit to get the job done, no matter what that job happens to be. Despite all his bravado, Kamina is genuinely devoted to the quiet Simon and vice versa. They know how to play off each other's strengths and together they make an almost unstoppable team.
Gurren Lagann is a successful series that has something for everyone. The mix of drama and comedy, interesting characters, and eye-popping artwork will delight both hardcore anime fanatics and newbies to the form.