Hikari Ban (Mei Hata) is a high school student in grade 3 class C. She suffers from an inherited disease and is informed that she has only 1 year left to live. Hikari Ban secretly makes a list of things to do before she dies. She tries to spend every day as the best day and people around her call her a positive monster because of it. She holds a crush on her classmate Taishi Fujiwara (Coki Yamashita).