Shinichi Chiaki and his music friends, including Megumi Noda, are sent to the Nina Lutz Music Festival in Nagano to learn from other renowned conductors. During their trip, they take a detour to a beach in Niigata, where they spend the day. Chiaki, who's afraid of the sea, stays inside while the others enjoy the activities. Megumi suggests renting an inflatable boat to visit a nearby island, which puts Chiaki's secret to the test.