On a damp London morning, private investigator Benjamin Browning finds himself in the midst of a wildly chaotic ride with his friend Freddie, whose erratic driving mirrors his unpredictable temperament. After a hasty drop-off at his office, Benjamin's day takes an unexpected turn when he collides with writer Jackie Howard, setting the stage for a series of remarkable events. When Benjamin expresses interest in taking Jackie out, she gently refuses, suggesting he wait for her return from Paris. Back at the office, his dependable secretary Margaret steps out for a lunch break, leaving Benjamin to contemplate his next steps.
Suddenly, Quimby Charles (portrayed by Richard Vernon), a self-identified Member of Parliament, materializes with an enticing offer to be a bodyguard for the mysterious Mrs. Patricia Elliot (played by Marguerite Corriveau). Despite hesitations about the job, Benjamin accepts and visits Patricia's residence, where he shockingly discovers her lifeless body, the victim of a brutal murder. To add to the grim situation, he himself meets a fatal end, succumbing to a stab wound.
In a peculiar twist, Benjamin awakens in an "intermediate destination evaluation facility" overseen by the compassionate Mr. Higgins. Curiosity drives Benjamin to understand his new reality: he has been granted a second chance to solve his own murder and determine his fate in either heaven or hell. While examining a front-page report detailing his demise, he realizes that Quimby was an imposter, propelling him back to life in the form of a dog.
Transforming into Browning the dog, he finds himself in Paris, where he cleverly hops into Jackie's car. Back in London, the human Benjamin is nowhere to be found, but Freddie eagerly shares news of recent events, guiding Browning to Patricia's apartment. Here, he painstakingly searches for clues while Malcolm Bart (played by Omar Sharif), the mastermind behind Quimby's deception, lurks in a closet, relishing the game. During this time, Browning uncovers a crucial phone number written in Patricia's calendar dated just before his murder. Dialing it on a rotary phone, he learns it belongs to the Needham Gallery. Fortune smiles upon Browning when Jackie arrives, leading to electric tension as she engages with the gallery's manager, who threatens to involve Scotland Yard.
Amidst this unfolding investigation, Margaret meticulously sorts through remnants of Benjamin's office, while Jackie shows up, eager to interview her about the shocking murder that has gripped the city. As they talk, Margaret reveals a photograph of Benjamin, leading Jackie to recall that they had met shortly before his tragic end.
The conversation shifts focus when Jackie discloses her residence at the affluent Stanley Towers, prompting Browning to track her activities. Meanwhile, Jackie visits Scotland Yard to meet Quimby, who seeks access to her findings, desperate to clear himself of suspicion.
As the plot thickens, Jackie wanders into the Needham Gallery, leaving Browning behind in her parked vehicle. During her visit, she converses with the enigmatic artist Montanero, extending an invitation to dinner, all while Browning remains hidden, watching their every move. Soon after, he comes face to face with Alistair Becket, an ambitious politician with aspirations for the highest office, who shows considerable interest in Jackie's literary pursuits, charming her entirely.
While Browning tailgates Jackie, he grows increasingly convinced that she harbors secrets of her own. His hunch is substantiated when he witnesses her interacting with none other than Bart, the murderer. Startled by the presence of the dog, Bart makes a hasty retreat, offering Browning the chance to continue his pursuit of the truth.
Over the ensuing days, Jackie wrestles with gaining access to Patricia's client ledger, now securely held by the building manager. Unfazed, she enlists Becket's help, only to find Bart, Becket's assistant, adding to Browning's growing unease.
As the investigation builds towards its climax, Browning stumbles upon a painting of the Swiss Alps hanging in Becket's office, recalling that Patricia had vacationed there just prior to her death. This connection ignites his imagination, suggesting deeper layers to the crime at hand.
Eventually, Browning ventures into Patricia's flat, catching Bart red-handed as he attempts to dispose of incriminating evidence. Just when hope seems lost, Mr. Higgins reappears to urge Browning to flee the scene as his time runs out. Defiant, Benjamin insists he'll not rest until the truth prevails.
While Becket discreetly informs Jackie that her furry companion is in trouble with building security, Browning uncovers Bart's desk calendar, revealing an ominous entry—a birthday and address connected to Becket. Jackie, unaware, congratulates Becket on his birthday, prompting him to clarify the true date as they head off for lunch, while Browning devises a plan.
Browning's investigation leads him to the post office where he unearths a letter containing Patricia's distinctive pendant with the cryptic abbreviation "ALP." As he deciphers this message, it becomes evident that Alistair loves Patricia. This shocking revelation causes him to scrutinize Jackie's police snaps, confirming that Patricia had discarded the pendant.
Browning quickly concludes that Becket, desiring the prime minister's mantle, conspired with Bart to eliminate Patricia. As truths unearth, Browning seizes the pendant, rushing toward Jackie's lunch meeting only to encounter Bart, who pursues him relentlessly through an alleyway. There, Browning reverts back into human form only to be confronted again by Mr. Higgins, who forewarns him that time is running out.
In a twist of fate, Benjamin reappears at the restaurant with the pendant, just as Becket accuses Jackie of thwarting his political ambitions. During a volatile exchange, Browning inadvertently captures Becket’s confession on tape, unraveling the tangled web of betrayal. The veil lifts further when Bart confides in Jackie, revealing his manipulation of Becket.
What follows is tragic irony, as Bart's attempted elimination of Browning instead injures Jackie. Left shaken by loss, Browning finds solace in reuniting with Jackie, who returns to Earth as a cat, her spirit now free to wander at last.
