Niko runs excitedly through the apartment, because the guests are about to arrive. It's his eighth birthday and he wants to celebrate it! He has invited his best friend and his best girlfriend. His father actually wanted to help with the preparations, but what is he doing in the yard for so long now?
When everyone finally gathers in the living room and starts singing the birthday song, the doorbell rings: The neighbor girl, of all people, is at the door! She has accidentally locked herself out of the apartment. Niko's father invites her in so that she doesn't have to wait alone in the hallway for her mother. Niko can hardly say no. A quarrel seems to be inevitable, and the party that he had imagined so beautifully gets pretty much out of hand in the course of the afternoon.
At the end of the day, the children not only find a treasure, but they also find each other again and anew in an unexpected way.