A man gets used to jot down everything in his notebook. One day, he meets an absent-minded lady in a coffee shop and plans to return her lost keys to her. He finds that the door of the lady's home is not locked, so he walks in and posts notes to help remind her about different things... On the next day, the man loses his notebook ...然習慣把生活中每件事情用筆記本記錄下來。每天，他在同一間咖啡店埋頭寫小說。某日，然在那裡認識了一個很善忘的女侍應生樂。該店的老闆發現樂遺留家中鑰匙，請然幫忙把鑰匙送還給她。他到了樂家，發現大門沒有上鎖，推門進去……樂回到家裡，發現全屋貼滿了黃色便條，提示她該做的事情。某天，然發現遺失筆記本……
