 Charles-Victor told his mother he s far too adult for a childish birthday party among family, but when he hears one is being prepared at Jeanne s, assuming it s for him, he s elated. In fact Jeanne, Betty and Sam plan a surprise party for Odilon s fiftieth birthday, but their obsessive secrecy leads to Billy believing it s for him (although not on his birth date), Jef believing Jeanne forget about him and planning one with Koen, and a further comedy of errors till the twist at the end.