The secret from the title is the lost recipe for shiny Delft pottery, that Jan Vogel is desperately trying to rediscover. For his attempts he needs...

When his granddaughter is born, debt-ridden Colonel von Zwenken misses out on Aunt Roselaar's allowance of 20,000 guilders. Anxious to keep the...

Lona, a young woman who has no memories of her past, has been adopted by the rich industrialist Van Haaften. She is loved by Henri van Rhenen, a...

On the verge of getting married to Marijke, young and insecure detective Jozef is assigned the case of a murdered factory girl. His relationship is...

Ducrot and Ninette accuse Mario and Anny of owing their wealth to the murderous effects of Mario's bombs. Anny leaves for the front to care for the...

Beppie, Margie and Lola, the three talented daughters of American millionaire James Brown, set course to Amsterdam with their art teacher ms. Polly...

The wealthy De Roquevilles, the family of alcoholic veteran Jean Laurent, and that of farmer Godard; all have to deal with the outbreak of the Great...

Anny helps Mario escape from prison after his attempted murder of Gaston de Roqueville, who is now married to Ninette. Banker Sorga, an enemy spy,...

The happy life of Sylvia and Pieter is disrupted when Sylvia loses her sight and her sister Lyda falls in love with her husband.

Married housewife Alda decides to become a singer under the stage name 'La Renzoni', in a duo-act with her father. All goes well, until her husband...

When self-made businessman Pancras Duif decides to marry his much younger housekeeper, his entire family protests; eager to protect the family...

The guests at Count Otto von Trepow's East Prussian estate Gross-Ehrenfeld are Lord and Lady Ruthven, Mr Hendriks with his wife and foster-daughter...