When a journalist dies, his brother takes up his investigation of a smuggling ring.

In London, American commercial artist Tim Forrester draws model Jill Stewart for a beer ad. Although Tim is attracted to Jill, he has remained unresponsive to her attempts to seduce him for so long that she has begun dating wealthy Henry Carmichael, who soon arrives and proposes. As they leave, Tim's brother, pilot Dave Forrester, delivers the news that their other brother Lewis has been killed in a car crash in Milan. Lewis was an investigative reporter, and his newspaper is sending employee Fenby, along with Dave, to arrange the funeral. Before leaving, Dave learns that another woman, British actress Alison Ford, was in the car with Lewis when it crashed. In Italy, police captain Brunetti informs Dave that both bodies were burned too badly to identify, and that the case is closed. Meanwhile, at Scotland Yard, Inspector Colby deduces that Lewis' death was a murder, and is probably connected to the jewel-smuggling ring the reporter was investigating. Colby soon receives a phone call from Brunetti, who reports that on the day of his death, Lewis sent a postcard to London with a sketch of a Chianti bottle held by a woman's hand. As Tim finishes the beer ad at his apartment, Jill bids him goodbye, but cannot resist kissing him. The kiss is interrupted by Colby, who has come to see if Tim received the postcard, but Tim replies that he knows nothing about it. Later, Tim is invited to the hotel of John Smith, who commissions a portrait of his daughter, revealing that she is Alison. Smith gives Tim her photo and pink dress to paint from, and Tim, intrigued, begins work. Soon, Jill visits to pick up a few belongings, and after admiring Alison's dress, accidentally leaves behind a package for Carmichael she has received in the mail. Later that day, Alison, who is still alive, rushes into Tim's flat and, seeing her portrait, ruins it then steals the photo and dress. When Tim returns with Dave, they are horrified to discover Jill, wearing the pink dress, dead on the floor. Tim's alibi, that he was driving around town, is mistrusted by Colby, who discovers in the apartment a charm depicting a bird in a cage. He then insists on opening Carmichael's unmarked package, which contains a bottle of Chianti. Colby calls Tim into his office and openly doubts his story about Smith, who is no longer at the hotel. He also calls in Carmichael, who denies knowledge of the Chianti bottle and insinuates that Tim killed Jill in a jealous rage. Tim soon receives a phone call from Reg Dorking about Lewis, and when he visits Dorking's office, the sleazy car salesman offers to retrieve the postcard for Tim at a cost of £1500. Tim agrees to get the money by the next night, then informs Colby about the extortion. Colby arranges to have a recording device installed in Dorking's office, but the car salesman deduces the ploy, and when Tim shows up with the money, lies that Tim asked him to find the card. Colby, assuming that Tim has set up the situation in an attempt to feign his innocence, then informs Tim that Jill bought the pink dress herself in a nearby store, and advises him to get a lawyer. That night, Alison comes to Tim's and explains that she met Lewis in Italy while on vacation with her father, and fell in love. Lewis' investigation took him to Milan, and he invited her to drive there with him. Although her father protested vehemently, she insisted, but along the way they quarreled and she got out of the car. She assumes that Lewis' companion must have been a hitchhiker, and wonders if her father had known that the car would crash, in which case he must be connected to the smugglers. Alison has been unable to locate her father and is afraid to alert the police to his existence. Tim takes Alison to dinner, where she reminisces about the night when Lewis drew on the postcard her hand holding a bottle, which he then sent to Fenby. Tim questions Alison about her charm bracelet, and she admits that she recently lost a charm of a caged bird. Worried for her safety, Tim invites Alison to spend the night with him, and at his flat, she reveals that she was there the night of Jill's murder, but ran away after spotting the body. Relieved to have part of the mystery explained, Tim invites Colby to meet Alison in the morning, and although she is gone when the inspector arrives, he sees her passport and believes Tim. Dave visits, and after overhearing Tim tell Colby about the postcard, goes to Fenby's house, where he demands the postcard. When Fenby tells him he recently mailed it to Tim, Dave, a member of the smuggling ring, kills him. Meanwhile, Alison finds her father at his hotel. When she confronts him about the smuggling ring, he confesses that he works for a ruthless man named Nightingale. Tim soon locates Alison at the hotel, and as they are talking, Smith jumps from his window and, near death, is taken to the hospital. Back at his flat, Tim finds Dave, who declares that he is moving to South America for a job. Just then, the mail arrives, and when Dave sees the postcard, he orders Tim to give it to him. Dave then finally admits his connection to the smuggling ring, and states that the names of its members were encoded by Lewis on the postcard. Dave attempts to grab the postcard, but Tim restrains him and calls Colby. The inspector soon decodes the smugglers' names, and upon seeing that the head of the ring is called Nightingale, launches an investigation into his true identity. When Alison later returns to Tim's, she finds Carmichael there, and recalls that she met him in Italy while with her father. As soon as Carmichael realizes that she has recognized him as Nightingale, he declares that, as he earlier killed Jill in this flat, he will now kill her. She manages to fend him off until Tim arrives, at which point Carmichael attacks Tim. The two fight until Tim accidentally pushes Carmichael out the window to his death. After the investigation is officially ended, Tim invites Alison to stay with him until he can finish her portrait, a job he hopes will last a lifetime.