Dr. Lydie offers unemployed children's doctor Thea a job in her practice. Koos buys an old van from Jopie. A man arrives to demonstrate a new revolutionary knife, but Lydie has forgotten to arrange an audience for him.
Mien goes shopping with her Turkish friend Hülya. Hans's sister Çanci is coming to stay and Lydie, Gert Jan & Koos all offer to provide her a place to stay. But Pien becomes jealous and Mien also objects.
Hans is going away for a week and Gert Jan & Pien are sleeping in Leiden. Lydie has a hangover from the going away dinner and has lost her keys. Koos and Mien are nervous about burglaries and insist on a new lock and keys.
Pregnant Pien is feeling bored and wants to teach Aerobics classes, but overprotective Gert Jan forbids it. When Gert Jan tells Pien to ask his mother for advice, Lydie wisely insists she goes for a second opinion.
While discussing a name for Gert Jan & Pien's unborn child, Lydie suggests they name it after her. Meanwhile Koos & Mien are suffering from a new neighbour who is loudly renovating his house day and night.
Koos is suffering from a stomach ache but is ashamed to pull down his trousers in front of Dr. Lydie. When Lydie and Hans diagnose a acute appendicitis, he is taken to the hospital, where Mien gets lost.