Part 1: Sho Hizuki is a 17 year old highschooler who has blood cancer and has been living with his little sister ever since their mother died and their father abandoned them since their mother died, and now he has to work to make a better living environment for his little sister while trying to make his own condition better. But in doing so, he ended isolated and with no friends at school and his job.

Part 2: A girl named Yūki Takina, who had the same condition as Sho Hizuki, appeared I his life and changing him to see the world from new perspective. But the only difference in their conditions was that she had a heart disease, but she didn't let it stop her from enjoying her life and making new friends.

Part 3: In the end, their all needed quick treatment before it was too late for them. But even so, they kept their condition to them selves without their new friends knowing about it, and as though as their situation was they started to fall for each other.