In Weelde, a village near Den Bosch, in the Catholic south of the Dutch kingdom, a bridge is planned, which would actually help the secret Nazi invasion plans. It's controversial in local politics, with the dominant Catholic conservative alliance of farmers and squire Van Weerde-Lawieck as formidable opponents. Powerful entrepreneur Nico Brenner is tipped off by an abused son in law that a crucial field sale isn't final yet and weighs on the banker to block it. New arrivals are Dutch government officials for the project and young northern doc Anton Meerdink, whose father-in-law bought him a medical practice there.
Annelies Brenner braves her dad Nico to marry squire Jan Van Weerde-Lawieck. The businessman sells her hand for the squire's land necessary for the bridge and some cash. Dr. Anton Meerdink enjoys entertaining Jaap ter Mors from Holland. They would abort Rosemarieke's baby, who may have a cognitive disability, but the vicar decides she'll give birth secretly in a convent.
Now the squire has sold the land across the river, work on the bridge starts. Guests flock to town for his wedding. Woudstra interests the squire, given the role of Prussian Junkers (nobility) in Hitler's Reich. The beggar-thief Douxdieu (pretending to be disabled) is mistakenly arrested for the bridge site arson he accidentally witnessed. The vicar goes to extraordinary lengths to save him. Dr. Anton Meerdink rows with his wife Loes, who absurdly blames him for her own apparent infertility and refusal to adopt, over sterilizing the mentally disabled.
Spring 1939, a Dutch parliamentary elections year. The pro-Nazi NSB supporters fight conservative Catholic farmers. Squire Jan isn't comfortable in his new role as NSB candidate, but his ambitious wife pushes him. An affair with Andton's maid gets farmer Bardoel's son Gijs evicted. After attending a lecture of his study lover Loes, Anton and she discover two grim secrets about retard Marieke in his retired predecessor's medical archive. Brenner is in trouble now the government insists on concrete, not steel for the bridge.
Spring 1939. Pressed for time, Brenner pushes his laborers must unhealthily, so the doctor gets a flow of exhausted and poisoned patients. The elections have finally arrived. As the vicar hinted, the squire isn't relevantly popular: his NSB list looses. Infertile wife Loes convinces Anton to adopt: the retard's plausibly also handicapped baby. His mistress not only keeps welcoming him in bed, she has crucial news, and isn't the only relevant one who tells Anton he knows.
June 1939. Marieke, who has a cognitive disability, gives birth to a physically healthy girl, so Loes can adopt. After one of Brenner's bridge laborers dies, Dr. Meerdink breaks his blackmail hold by confessing his adulterous impending fatherhood. The squire wants out of the NSB link, but his wife falls for Woudstra's party successor Jaap ter Mors's macho lieutenant's horsemanship and becomes his lover.
Spring 1940. Dr. Meerdink asks his mate Jaap in vain to use his NSB influence to have the government cancel the bridge. Anton and the curate appeal to the laborers, also in vain. The broke, lush squire sells his castle, half goes to his wife. Anton's wife ends up taking the curate's advice to return home, even gives up Marieke's adoption. The Nazi invasion is impending, but the squire and his butler are leaving to France.
May 8, 1940. Brenner's bridge is finally ready, but will only be open a few hours for the festive initiation. The undertaker's suicide ruins a relative's wedding. The Dutch army mobilizes against the Nazis, and guards the bridge. The NSB expects its hour of glory. Anton realizes from his code name that singer Kurt Weber is a Nazi spy. He, Brenner and the curate decide to sabotage it, despite the army ban to approach.