The students get together in their swimsuits for swimming class. The sea kids are still getting used to school on land, but are starting to get along with the other kids. The teacher mentions that he's going to be timing them today and as the kids groan in response, Hikari and Tsumugu's rivalry fires up.

Tsumugu dives into the sea after Chisaki. He starts having trouble breathing and is about to lose consciousness, but then suddenly gains Ena. Tsumugu finally catches up to Chisaki and lets her know his feelings while they're in Shioshishio. Chisaki cries and runs away.