Honeymoon with a Stranger

Ernesto, a multimillionaire, and his new wife Sandra arrive at a spacious villa in Batres, Spain. They are warmly greeted by the elderly servant Juanito, but their first moments are disrupted by frequent blasting from road widening nearby. The opulent setting frames the mystery to come.

After a night of heavy drinking, Ernesto and Sandra retire to bed. In the middle of the night, Ernesto's Rolls-Royce drives off and he vanishes, leaving Sandra to wake to an empty house. The missing husband becomes the central mystery that drives the plot.

Sandra reports the disappearance to the local police, triggering an investigation. Captain Sevilla is alerted, and Ernesto's attorney Frederico explains Ernesto's history of wooing women and vanishing, noting Carla, Ernesto's sister, will be contacted to locate him. The case begins to hinge on identity and intent.

Ernesto returns to the villa but Sandra presses her claim that he is an imposter. He argues the marriage was impulsive and expresses remorse. Sevilla is invited to dinner, and Frederico promises to offer an annulment settlement the following day.

The sergeant persuades Captain Sevilla to acquire a police siren and rotating light for the department's lone car to project authority. Sevilla reluctantly agrees, highlighting how far the case has moved from ordinary police work. The tone of the investigation shifts with this utilitarian win.

Frederico offers $25,000 in exchange for an annulment, but Sandra refuses. She intends to use Juanito to identify Ernesto as an imposter, hoping to expose him. Yet at the villa, Ernesto as well as Carla are soon set to arrive, keeping secrets for now.

At a cafe, Carla greets Ernesto as if he were genuine, reinforcing the masquerade for the moment. Sandra accuses the trio of conspiracy, while the other figures gather to confirm Ernesto’s identity. Tensions rise as truth feels increasingly elusive.

Back at the villa, a new settlement is proposed that adds the villa to the monetary terms. Sandra refuses, prompting Frederico to threaten commitment to a mental institution if she does not settle. The fake Ernesto further confesses something about a past injury, revealing Antonio as a stand-in used to shield those seeking revenge.

Carla declares she wants to keep the villa, leading to the withdrawal of the settlement. Sevilla contemplates the case as night falls and spots Ernesto’s Rolls-Royce, noticing a loose Spirit of Ecstasy hood ornament that hints at a deeper deception.

Sevilla reasons that the loose hood ornament proves there were two differing Rolls-Royce cars, implying two Ernestos. The trio proposes another agreement, but Sandra tears up the contract, and Antonio threatens her with a lit cigarillo, prompting a tense showdown.

Sandra reveals she studied Ernesto for a year to learn his patterns of leaving lovers. She drugged his champagne, drove him to a mountain road, and pushed the Rolls-Royce off the edge to fake an accident. She believed she had allies in the masquerade and could manipulate Sevilla by feigning vulnerability.

Sevilla heads toward the demolition site planned to reveal a possible body while investigating the two-Ernesto theory. Sandra fears exposure and again tries to incapacitate him with drugged champagne, but the plan escalates as she orders attempts to eliminate the investigator.

A wheel gets stuck on a rock as Sandra attempts to move a car; a new siren alerting the town finally sounds, drawing attention. Sevilla wakes, confronts Sandra at the road’s edge, and she experiences a nervous breakdown before being taken into custody.

Sandra is brought into custody, and Sevilla’s investigation culminates in the unraveling of the murderous plot. The scene ends with the truth behind the impostor and the murder laid bare and the authorities securing the outcome.