改編自全球首部LINE連載同名小說，30歲的郵差少年（佐藤健飾），在母親過世後搬出家裡獨自居住，而陪伴在身旁的，是他養的一隻小貓。一天，少年因病就醫卻意外檢查出腦中有惡性腫瘤，青天霹靂的消息也讓他招架不住，生活似乎失去意義。此時，少年遇見一名長相跟他一模一樣的神秘男子，號稱自己是「死神」，並提出惡魔般的交易：只要少年讓一樣東西在世界上消失，他就可以多活一天。半信半疑的少年試探性地說出希望消失的物品，沒想到馬上真的就不見了。就這樣，他又多存活在世上幾天，而就在手邊的物品都已經消失之際，「死神」竟提議要讓貓在這個世上徹底消失…

A postman learns that he doesn't have much time left to live due to a terminal illness. A devil then appears in front of him and offers to extend his life if he picks something in the world that will disappear. The man thinks about his relationships with ex-friends, ex-lovers, relatives and colleagues who will be sincerely sad when he dies.