This drama is a grand love story inspired by the world view of HY's famous song "366 Days". It tells the story of 28-year-old Yukihira Asuka who reunites with her former classmate Mizuno Haruto at a high school reunion. After the two learned that they were secretly in love with each other at the time, they decided to start dating 12 years later. However, one day Haruto encountered an unexpected tragedy and fell into a coma. Asuka stayed by his side when he did not wake up, and remembered the past times that Haruto and his classmates had forgotten...