Grand Blue Season 1 Episode 2

Underwater

After a cutthroat battle with Kohei Imamura, a handsome otaku from school, Iori ends up joining the Peek-a-Boo diving club. Iori arrives home worn out from the day, but perks up when he hears about a party with a women's college. However, his cousin Nanaka won't allow him to stay out three nights in a row, so Iori tries to show her he's an independent man to get her to let him go.