Max can hardly believe his luck: In a retirement home, he has finally found a gang that will let him join! Admittedly, it's the oldest and most wrinkly gang in the world - but that doesn't matter. He's found the best friends a 10-year-old could wish for in the elderly Vera, Horst and Kilian. Especially when, like Max, you're bullied in your new class and need help. But the gang's attempt to improve his school situation backfires. Horst, a former Bundesliga soccer coach, challenges Max's over-ambitious gym teacher Stöhle to a soccer duel: the school team including Laura and Ole against a selection of old geezers plus Max! And then the castle is haunted and a new case begins...
Marianne and Günter, a married couple in their seventies, have completely forgotten why they once fell in love with each other. On their wedding day, they want to get their memories back using a supposed "miracle pill" against forgetfulness.
Nine-year-old Max moves to Geroldseck Castle, together with his mother, who takes up a position as a geriatric nurse there. Apparently a shrewd thief is up to mischief here. His mother is suspected, she is threatened with dismissal. Therefore, together with the three residents of the old people's home at table no. 7, Max does everything possible to convict the real perpetrator.
Retirees Karin, Gerhard and Philippa are not in the mood for Nordic walking and seniors' courses at the university. When Philippa, who is living life to the full as Leonie's godmother, helps the two to unexpected grandparenthood, they suddenly have two "lively" god-grandchildren to look after, a huge bouncy castle standing in the garden and Lego bricks stuck to their feet.