Age
17
The 17-year-old girlfriend of Arashi Aota, and the main character of the chapters about Team Spring. She is depicted as beautiful, attractive and strong-willed; she is described as a tomboy by Arashi and energetic by Fujiko and Haru. Hana learned an adequate amount of wilderness survival skills from her father during her childhood. She was on her school swim team and dabbled in rock climbing as a hobby. Her usual motto is to never give up whatever happens to her. But when she realizes that she may never meet Arashi again, she contemplates suicide momentarily. She soon regains her vigor, once she learns that Arashi she has survived. As the series progresses, she becomes determined to live in the new world, and finds living on her own easier than having to deal with others.

7 Seeds
In the immediate future, a giant meteorite has collided with earth. All living organisms, including mankind, have been wiped off the face of the planet. The government, who had foreseen this outcome, took measures to counter the worst-case scenario. In particular was Project "7SEEDS," in which five sets of seven young men and women were carefully selected and placed into teams (Spring, Summer A, Summer B, Autumn and Winter). Each participant was then put under cryogenic sleep in hopes of preserving the continued existence of mankind. When those men and women awoke, they found themselves suddenly thrust into a cruel world. While bereft and grieved over forever losing their loved ones, they sought to find ways to survive.