Two years after the world as we know it has ended, Shizuru leads an uneventful life in her hometown of Agano. But one day, she finds a clue that will lead her on a journey into the unknown to find her missing friend.

Shizuru and the others depart on their journey to Ikebukuro, but find that they are woefully lacking in supplies. As they ride along the Koma River, they spot a mysterious, long-necked shadow.

The gang finds themselves welcomed by the friendly townsfolk of Higashi-Agano. Akira, however, can't shake the feeling that all is not as it seems with their generous hosts.