Sounan desu ka?

A school trip ends in disaster, leaving Homare, Asuka, Mutsu and Shion stranded on an uninhabited island. With hunger and thirst setting in, Homare remains surprisingly composed: her father has taught her how to survive in extreme conditions.

She guides the others through finding water, gathering food and making shelter, though practical advice does not always sit comfortably with their habits and fears. Successes, mishaps and reluctant experiments gradually teach the four girls how to keep one another alive.