Filmfabriek-Hollandia

The adventures of two girls from Zeeland in Zandvoort.

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 money, his son-in-law telegraphs the aunt that a son was born, Frans, and the girl is brought up as a boy. Based on the novel by Anna L.G. Bosboom-Toussaint.

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 platinum, but the funds run out because the factory owner Van Haaften has lost his money in stock-speculations. Luckily for Jan, he finds a farewell letter in the park, including a large sum of money. Meanwhile, the owner's son Leo confesses his love for Jan's daughter Annie, but Van Haaften forbids their marriage.

An orthodox Jewish man refuses to accept the marriage of his daughter to a Christian man.

In the prologue, a boat with some shipwrecked persons is drifting at sea. Among them is Baron van Waldheim, who, before he dies of exhaustion, entrusts his little son Alfred to the care of his butler Hendrik. The evil Jan van Oort persuades Hendrik to give him the Baron's papers. When they put the boy ashore, he wounds himself on a nail (leaving a scar that will later prove his identity). For years Van Oort manages to pass himself off as Baron van Waldheim; he is married and has a daughter and a son. One day Hendrik turns up demanding a job as butler, swearing that otherwise he will betray Van Oort's secret. Meanwhile, Alfred - now an adult known as Ulbo Garvema - has become a teacher. Unaware of who Van Oort really is, he accepts the position of tutor to Van Oort's children. He falls in love with the daughter, but Van Oort refuses to give his consent to their marriage. Ulbo and the girl elope.

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 threatened when he becomes madly infatuated with Carmen, the alluring prime suspect.

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 neighbour whose mother still mourns the loss of her daughter, who disappeared twenty years ago under mysterious circumstances. Lona has another suitor, Frans van Borselen, who hopes to marry her so that he can pay his gambling debts with her foster-father's money. Van Haaften discovers that Frans has been cheating at cards and offers him a revolver so that he can end his life honourably.

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 mistakes her father for her lover...

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

A poor fisherman's wife sends the remaining family members, her two sons, out to sea on a boat that has seen better days.

The storyline is about a man without a head that haunts the castle Arco in the 16th century. A man in the present day (1914) goes to the castle to find out if the story is true after which he finds something strange beneath the old castle floor.

Young poacher Hendrik van Norden has seriously wounded a game-keeper, who has not recognized him. There was, however, one witness: captain Van Oort, but he promises to keep silent. Five years later Hendrik has become a lighthouse-keeper and is courting Annie. Van Oort is also trying to win Annie's affections, and in his jealousy he decides to remind Hendrik of what he knows about his past...

When Jacques, the ladies' tailor of fashion house "The Four Seasons", wins 100,000 guilders in the lottery, his world is suddenly full of opportunity. Shop owner Madame Georgette, however, tries to trick him into signing a rather unfavourable contract.

The inhabitants of Amsterdam enjoy themselves on the ice on the Herengracht. Skaters in Amsterdam get ready for their trip to Monnickendam and Marken. Along the way, the skaters pass by Ilpendam. In Broek in Waterland, skaters cross a bridge to reach another piece of ice. A cake-and-snacks stand sells hot chocolate.