Cooro, Husky and Senri arrive in the large town of Octopus. Cooro and Senri standing waiting in the street. Cooro is impressed when he sees some children pickpocket a man, he tries to point them out to Senri, but he doesn't see. Husky returns after buying new clothes, Cooro asks whether he had sold the pearls, but he had only sold his earrings. Cooro suggested they buy something to eat. A person sitting in the darkness overhears the word "pearls".
They sit on some stairs eating bread, and Senri takes out his book. Two children run into them causing them to drop their things, and two other children waiting at the bottom of the stair pick them up and run away. They chase the children to some tunnels which Cooro likens to a maze. The children had split up, and Senri went in a different direction. Husky hears something behind him and looks into the darkness, but then he starts to feel dizzy. Cooro helps him to his feet, but then they are both grabbed by someone.
The child with the book sits down and tries to read it, but can't. Senri jumps down with a crash behind her. He utters just the word "book". The child runs away.
A teenage girl, Delly, holds onto Cooro and Husky, stopping them from walking into a nest of green leeches. Two of Delly's friends show up and claim the area as theirs. They offer to guide Cooro and Husky back to the surface, but are refused. Cooro and Husky insist on looking for Senri and the child. The girls recognize the description of the child, she is a young girl called Sammy, and they rush off.
Sammy runs from Senri but reaches a dead end. She knows the area is dangerous, so she cries and offers the book back to Senri. Some green leeches crawl out of the water behind her an pull her in. Senri leaps to save her. He remembers being given the book as a child.
Delly and the others continue searching. Husky worries about getting separated, since they have come very far into the tunnels. They find Sammy hugging Senri, while surrounded by the remains of many leeches. Sammy hands the book back to Senri, and runs to embrace Delly who hits her on the head, scolds her, and then hugs her.
Delly takes them back to her base, and explains they are all orphan girls, but will let them stay the night as thanks for saving Sammy. Another girl walks in holding their bread, Delly scolds her for stealing from children. Cooro recognizes the pickpocket from earlier, and Husky checks to find that his pearls are gone. He starts shouting at Delly to return his pearls; she asks around but no-one had stolen any pearls. Delly has a thought about who may have stolen Husky's pearls.