What is the Island Arc (Siren Arc)? Synopsis and Best Scenes Summary | When & Which Manga Volume [Chiikawa]

After seeing an island recruitment notice that Usagi brought, offering 'hundredfold rewards and free meals,' Chiikawa and friends travel to the island on a bird-shaped ship. Upon arrival, they receive flower garlands and waist ornaments from the islanders, and at the feast, island-exclusive ramen and fruit parfaits keep coming. Chiikawa, seemingly suffering from seasickness, curls up, and Hachiware stays by their side, searching for something they can eat.

At night, Chiikawa, Hachiware, and Usagi enter a cave, board a small boat, and hear the song of a Mermaid who emerges from the water's surface. Then a large Siren appears and chases the small boat, later recounting that one of their companion Mermaids has disappeared. They are informed that island residents are being abducted one after another, and Chiikawa and friends are asked to carry out the Subjugation of the culprit.

Armed with weapons provided by the island side, the group proceeds into caves and along the waterside to search for the missing. Chiikawa, separated from the group in the forest, meets Shimajiro at a shellfish soup shop and receives help searching for their friends' whereabouts. Afterward, as a measure to stop the Siren, they join forces with the islanders and begin making spicy curry, with Kurimanju as head chef and Shisa as taste tester.