Fujio Hanaoka, Seiji Kirihara, Shinya Oochi, Masaya Oochi, Madoka Ishii and Arata Maekawa are friends and they grew up together. They gather together to celebrate Seiji's birthday. The friends dig out a time a capsule they buried 10 years ago. They also write a letter to themselves for 10 years in the future and place it into a new time capsule. Afterwards, the friends experience tragedy.