Simon attempts to flee from the two ganmen that appeared at the end of the previous episode, but is chastised by Kamina, who faces them with only his sword. Yoko attempts to keep the ganmen at bay, but the Lagann runs out of power. Fortunately, friends from Yoko's village rain gunfire on the ganmen and they flee. An effeminate man named Leeron invites Kamina and Simon to stay in their village, Rittona, for the night. Yoko explains that the ganmen are piloted by beings known as Beastmen.
That night while on their way to the village, Kamina attempts to cheer Simon up, but it isn't until Yoko asks Simon to help remove the remains of the ganmen from the first episode that he manages to get the Lagann going again…after he takes note of Yoko's curvaceous body. The traveling party arrives at the remains of a human who Yoko says was probably attacked by a ganmen. She tells Kamina that the surface isn't as wonderful as he might think, and explains that Rittona used to be an underground village until an accident forced them above ground. Now they do battle with the Beastmen every day, fighting to survive.
Everyone finally arrives at the village, and Simon and Kamina fall asleep before they can even get food. Kamina dreams of being taken to the surface by his father as a small child. His father sent him back below ground and went onto the surface himself, telling Kamina to make his way up when he's ready. The next morning the two are awoken by the arrival of Beastmen and Simon tries to pilot the Lagann, only to have it fail again.
Simon then sees the gunmen and realizes that one of them caused the earthquake that killed his parents. He gets fired up and the Lagann is able to run again. Kamina decides that he wants to take one of the Beastmen's gunmen for himself, and tells Simon to get him close to it. Kamina gets into the gunmen but its controls lock up so he can't use it. The Beastmen start to beat up on Kamina, but then he notices a skull on the ground that triggers his own emotions, allowing him to gain control of the gunmen. Kamina and Simon defeat the Beastmen, and Kamina names his new gunmen Gurren, but then he notices a familiar bracelet and cloak on the remains he noticed earlier-- it's his father.