The entire Knots family has to cut down on expenses because Tante Til hasn't sold a single artwork in a while. On top of that Neef Herbert breaks Tante Til's antique vase she was planning to sell. Hansje is instructed to lure a lot of customers into the comic shop. Lucky for her, a wealthy little boy gets stuck between the elastic ropes Neef Herbert was playing with outside.
Meester Vogel is suffering from nightmares and confides in Grandma. She tells him all about the Knots family secret and more importantly, to ask Hansje out on a date. Cousin Herbert has found a set of Indian clothes and weapons to play with. The toy gun and bow and arrow are quickly confiscated by Onkel X, who always wanted to have a weapon of his own.
The entire Knots household is upset about one thing or the other. Grandpa hurts his knee while re-enacting his marriage proposal in front of Oma, so a doctor is send for. Soon the medic, Dr. Heman, begins to charm all the women in the household. Neef Herbert has got a present for Onkel X and Tante Til's 21st wedding anniversary. Tante Til is uncomfortable being reminded that their marriage has remains childless. Hansje is upset because Arend has moved out of his lodging without telling her.
Arend Vogel is moving into the attic. To his dismay, his nosy father comes over to visit uninvited. Onkel X and Opa are also snooping around in the young teacher's room. Hansje panics when she has misplaced her diary.
Arend Vogel calls in sick on account of a stomach ache. Neef Herbert jumps at the chance to nurse Vogel with his toy doctor's case. Grandpa is looking for his dog. Grandma is serving everybody her delicious new soup.
Cousin Herbert's obsession with toys has inspired Hansje to swap more than just comics in the Familie Knots swap shop. Herbert shows a different side to himself when he visits in a professional function with his colleague De Wit. They are investigating a possible case of fraud by Tante Til. Arend Vogel's tutoring also comes under scrutinizing. It turns out the tax forms were not posted in time. Now Tante Til needs her amateur sleuth husband Frederik more than ever, but unfortunately he is out.