On their way to Teppelin, the Beastmen's capital city, Team Dai-Gurren stumbles upon a vast ocean and must wait for modifications on the Dai-Gurren to be completed before crossing it. While the rest of the group play at the beach, Yoko starts to feel uneasy about Nia and all the attention she gets from them. After preparations are complete, Team Dai-Gurren begins their sea cruise, oblivious to the fact that an ambush is underway by Adiane and Viral.