Morbid Catholic writer Gerard Reve–bisexual, alcoholic, and experiencing frequent visions of death–is invited to give a lecture at the Vlissingen literature club. While in the Amsterdam railway station, he's attracted to a handsome man who embarks on another train. Gerard meets club treasurer and beautician Christine Halsslag, and engage in a one-night-stand. The next morning, Gerard sees a picture of Christine's boyfriend Herman and recognises him as the man at the train station. He urges her to bring Herman to her house to spend a couple of days together, but with ulterior intentions of seduction. During a night on his own, Gerard finds and watches film reels, discovering that Christine had married each; all of whom died in tragic accidents. Believing Christine is a Black Widow, Gerard begins to question whether Herman or he will be her doomed fourth man.

'The 4th Man' showcases Verhoeven's visionary direction at its finest, delivering a gripping mystery filled with surreal imagery and deliberate ambiguity that keeps viewers guessing throughout. The film's religious symbolism and explicit sexual content prove integral yet divisive, with some finding them boldly provocative while others consider them gratuitous or heavy-handed. Character depth receives mixed reactions, though performances, particularly from Jeroen Krabbé and Renée Soutendijk, earn widespread praise for their compelling portrayals in this intellectually engaging thriller.