Akari Mizunashi continues her training to become an undine on the terraformed planet Aqua (formerly called Mars). The story takes place during Akari's first winter on Aqua. She experiences new things, such as playing with snowbugs and going to a hot spring with her friends. But things get interesting when she encounters a trio of Gnomes, the underground dwellers responsible for maintaining Aqua's artifical gravity, and even gets a tour of the facilities!