Chaperoning a class trip to Hokkaido gives Nasa and Tsukasa the chance for some private lessons of their own. Nasa passes the test of driving on mountain roads, while Tsukasa completes a survey of local foods. But they have work to do as well, escorting Nasa’s students to the legendary Sea of Clouds. And every day with Tsukasa is a history lesson, as she recalls children she taught in the distant past…