While sailing out of the fog, the Harekaze encounters another ship of their school. Initially assuming to be the Musashi, it turns out to be the Hiei. The school orders the ship to monitor the Hiei while avoiding being hit as reinforcements from the Blue Mermaids were deployed, arriving in four hours. The crew realizes that their course was leading to a residential area and worries that the infection will spread from the Hiei to the residents. Meanwhile, Mashimo visits her mother, the principal at the school explaining the source of the infection and how it began. Meanwhile, Akeno devises a strategy and receives permission from the principal to execute it in order to stop the Hiei. The plan was successful with the Hiei running aground and the Blue Mermaids arrive, led by Mashiro's other elder sister, Mafuyu.