The pre-Christmas period in a household with four small, temperamental children creates a comedy in itself. But when problems with the password lock are added to the confusion, the fun is guaranteed. A busy father of a family buys one of these ingenious gadgets. This invention is supposed to make it impossible for his children to constantly search for Christmas presents. The tense atmosphere and the interplay of random circumstances mean that even trivial problems begin to take on completely different dimensions in the mother's eyes. The previously trusting wife interprets her husband's chess training, mysterious phone calls.... And to make matters worse, the father forgets the password to the lock. Everything culminates when the wife discovers a present under the tree that was probably intended for another woman. However, the mysteries are not solved until New Year's Eve, when - surprise surprise - the mother-in-law intervenes in the story.