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.
While Grandpa and Grandma are on a boat trip, nosy neighbor Ms. Pronk from no. 25 has been doing the cooking and cleaning for the Knots household. She has also been hinting at the possibility to send the elderly couple off to a home. Hansje and Meester Vogel have taken the opportunity to organize a party for the children in his class in the attic.
One of Arend Vogel's students, a punk girl named Jannie is protesting against him outside the Knots family's comic book shop. Grandpa objects to Grandma petting a canary called Pietepiet, because this means she is neglecting her housework even more than usual. However, Jannie inspires Grandma to take a stand against her husband.
Hansje, who has taken up night school, gets an offer to be a movie star from producer Marius Movie. He only needs to convince Arend Vogel to let her go. Frederik, aka 'Onkel X' wants to go back to work but gets rejected at every police station he applies to. Tante Til decides to introduce her Frederick to the film producer using her infamous pink paint.
Tante Til cannot concentrate on her art because Onkel X is practicing his lines. Even the infamous pink paint won't work for her anymore. Hansje breaks up with Arend because of a picture of another woman she found while cleaning his room. Grandpa is upset because Grandma has had too much to drink and nobody wants Neef Herbert Around.