Double the party, and double the setbacks, for the kids in Class 3C on Sharon's birthday. Invited by her partner to her parents' luxurious villa, they have to find a new home because their father is under the tax authorities' scrutiny when they arrive. The large group of guests, along with the buffet and the Zampettis' waiter, "move" en masse to Bruno's house, a more cramped space where dancing becomes a feat for contortionists. What's more, when it's time to dance, Bruno's parents and the tenants, who insist on holding a condominium meeting, enter the fray. Sharon thus experiences the most stressful birthday party of her life.