岳父岳母Bob and Greta De Jaegher are happily married for 40 years. They can look back on a rich and fulfilled life. Their 2 sons Steve and Carl have a successful life as well. Steve is a talented and recognized film-director and Carl is a promising cook. Steve's wife Billie wrote a bestseller about happiness and wants to start a family with her husband. Brother-in-law Rik, who works at the zoo, tries to pick up his life with his kids, after his wife died two years ago. To mark their 40th wedding anniversary, Bob and Greta organize a family weekend. They want to announce something very important. Their new plans are a sure hit for the family De Jaegher, but that's not the only thing - Wat had to be a cheerful gathering of the family, turns out to be something nobody expected.