Lisa Buloff, dressed entirely in black with a veil, attends a funeral for someone whose identity remains unspecified. This somber scene sets a tone of grief and mystery that permeates the entire story. The film begins weeks earlier with Willie Zoll, who is at a bar, preparing to share critical information with Inspector Franz Bulon, a dedicated officer leading the Hamburg narcotics division for Interpol. Zoll is on the verge of revealing the whereabouts of Harry Schouermann, a major figure in the drug world. Unfortunately, as Zoll steps into an alley to make his report, he is unexpectedly attacked and fatally stabbed by an unidentified assassin. The killer leaves behind the murder weapon and a cheap disguise, hinting at the dangerous web Zoll was trying to unravel.
Bulon, portrayed by John Mills, is visibly frustrated because Zoll was their best hope for cracking the case. The situation worsens as two other potential witnesses and whistleblowers are systematically silenced through contract killings, just before they could provide vital evidence. Bulon’s superior, Ostermeyer (played by Enzo Fiermonte), becomes angry and urges Bulon to pursue another lead urgently.
Back at home, Bulon confronts his wife, Lisa (Luciana Paluzzi), a woman with previous connections to Schouermann. Despite his belief that she isn’t involved in the criminal activities, Bulon’s paranoia leads him to become overbearing and controlling — tracking her movements and questioning her actions. His suspicions are heightened when she doesn’t answer the phone, which leads to a tense exchange where Lisa bitterly reminds him of his distrust. Their relationship is complex; later, they seem to reconcile, sharing intimacy after Bulon pours himself a drink, suggesting a fragile attempt at normalcy amidst the chaos.
The following day, Bulon’s suspicions increase when Lisa leaves abruptly after refusing to answer calls. In a moment of confusion, Bulon mistakenly questions a young woman, Marianne Loma (Vanna Polverosi), mistaking her for Lisa, and under pressure, she discloses that Ursula Stein picked up a package for her boyfriend, Kurt Mueller (Carlo Spadoni), who is a known target of the drug cartels. Lisa arrives later at the police station asking for money, and while Bulon engages her with questions about her activities, she defies his accusations, citing his jealous behavior and his obsession with work.
The police’s investigation intensifies when Ursula, in a state of distress, is assaulted and kidnapped by Schouermann’s henchmen. Bulon consults his informant, known as The Rabbit (Giuseppe Terranova), at a newsstand. The Rabbit hints at tulips being connected to the drug ring but remains evasive about Mueller out of fear. Meanwhile, Max Lindt (Robert Hoffmann), a cold and professional hitman, meets with his employer, Olaf (Rodolfo Licari), and agrees to one final murder — targeting Kurt Mueller.
A crucial clue emerges when Bulon discovers a note from Lisa hidden under a bouquet of tulips, indicating her secret departure from a restaurant. Investigating further, Bulon tracks down Mueller at a post office, where Lindt kills him, leaving behind crucial evidence linking him to the crime. The police manage to recover Mueller’s body and find a lucky dollar at the scene, which helps Bulon identify Lindt from security footage.
The tension escalates as Bulon confronts Lisa about her connection to the drug ring. Her response reveals her frustrations about their marriage and her desire to have an affair, which results in Bulon physically assaulting her. Meanwhile, Mueller, surprisingly, is still alive, leading Bulon to a breakthrough in the case. Lindt’s whereabouts become clearer when Bulon finds a note hinting at his hideout. He then targets Lindt, who has taken a vacation at a hotel, and manages to arrest him. During the ride to jail, Bulon glimpses Lisa entering a red Porsche, yet he loses her when she flees the scene.
Bulon’s investigation points to Irini von Klaus, a friend of Lisa, who owns the red Porsche. Realizing Lindt plans to harm Lisa, Bulon intervenes just in time. Despite their previous disagreements, Bulon apologizes to Lisa, but she criticizes his controlling and obsessive behavior. The Rabbit provides more details about the tulip connection, but he is soon killed by Schouermann’s enforcers, emphasizing the danger hanging over everyone involved.
As Lindt, still under the illusion that the hit is still on, visits Lisa’s house and begins an affair with her. Bulon, meanwhile, is relieved to find Lisa unharmed but soon finds himself at a standoff with Lindt, who shamelessly reveals the affair. Facing mounting pressure, Bulon forces Lindt to proceed with his original plan to kill Lisa. He documents his investigations in a report that exposes Schouermann, Lindt, and even some of his own questionable actions, attempting to protect Lisa by omitting critical details.
The situation takes a violent turn when Bulon confronts Lindt in an abandoned factory. In a brutal betrayal, Lindt slits Bulon’s throat and stabs him, vowing that Bulon will suffer for his deeds. Unknown to Bulon, Lisa is unaware of his fate and contacts Schouermann to meet again. This leads to the police chasing Lindt into the woods, where he is ultimately shot dead.
The story concludes with Lisa meeting Schouermann, who coldly rejects her and reveals Bulon’s involvement with Lindt. The film closes with Lisa attending Bulon’s funeral, standing quietly as Ostermeyer hints at corruption within the law enforcement agency, though he stops short of directly implicating Lisa. An alternative ending suggests that police come to arrest Schouermann and Lisa, following her late husband’s orders.
Throughout the narrative, John Mills as Bulon embodies a man torn between duty and paranoia, while the supporting cast including Luciana Paluzzi, Giuseppe Terranova, and Robert Hoffmann contribute to a tense, intricate plot filled with betrayal, violence, and moral ambiguity. The story explores themes of trust, betrayal, obsession, and the corrupting influence of power within the criminal underworld and law enforcement alike.
