Doraemon and Nobita try to find what happened to Dad's important work documents when it went missing. They travel to the previous night which was when Dad went on a happy hour with his boss and ask to safeguard his salary, but end up losing it after Dad finds out that the boys are loitering around in the night and being chased by a dog. It turns out that a policeman picked up the documents that Doraemon and Nobita dropped, and returned it to Dad.
