The chapter opens with a flashback to Hiroshi's first meeting with Mina. Hiroshi tells Mina that he wants to go to Umibozu's house to tell him that he's the cutest guy in town. Mina says that she's going to send him a picture of herself in a sexy pose, and Hiroshi says that's what he'll do. He also says that Mina is going to get paid leave soon, so he plans to write her off as an employee for the rest of the vacation. The flashback continues with Mina's description of the swimming pool, which she thinks is too shallow for kids to swim in. She compares it to a "life guard" , and she wonders if it's really a pool, or just a sauna, or something else entirely. She's a mermaid, after all. She tells Hiroshi that she used to be a swimmer back in high school, so she knows how hard it is to get in the water. He agrees to take a swim challenge with her, and they compete in a game of hook, line, and sinker. The game is so fast that Hiroshi can't keep up. He tells Mina to stay and talk to the station, and he suggests that they go look at the pool. He says that he knows they've been friends for a long time, and that he thinks they'll be able to get along well during the upcoming battle. He asks if they can just leave the pool alone, since the water has some sulfur in it, which would make it unsafe for them to put it in the sewer system. They decide to go check it out.