John Beal as Horace Jason and Wanda McKay as Millie Jason check into the Hotel Clarke in New York City, prepared to spend their first night together as a married couple before Horace heads off to join the Army.
To celebrate, they plan champagne. Millie dims the lights and changes clothes in the bedroom while Horace steps out to fetch the bottle. Suddenly, Pete Mooney [Ernie Adams] and Joe Richmond [Lynton Brent] slip in through a window, pull the unconscious body of Pierce Lyden as Duke Keesler from under the bed, and frisk him on the mattress until Horace returns. The room fills with tension as the hotel suddenly feels less like a honeymoon and more like a setup.
Back in the corridor, Horace and Millie rush to enlist help from the hotel detective, Warren Hymer in the role of Pat Callahan. They discover the body and realize something is terribly amiss, but before they can alert anyone, Mooney and Richmond hurriedly stuff the body into Millie’s empty trunk and vanish out the window. When Horace and Millie hurry back to the scene, the trunk has vanished as well, and Callahan leaves in a huff, convinced it’s all a misunderstanding.
A shocking turn follows: Horace opens the trunk to find the body of Duke Keesler, still alive, tumbling out and prompting a frantic chase. Keesler escapes out the window, while Horace and Millie race to tell Callahan what happened. In the chaos, the would-be rescue attempt becomes a prank of misdirection, and the couple end up locked in the room with a mounting sense of danger.
Mooney and Richmond reappear, taking the trunk away to an unlikely destination—Frankie Saxton’s hangout. Frankie Saxton, a gangster, is played by Tom Neal. They also hand over the case, believing Keesler is still inside. The trunk is opened, and Horace tries to explain that a terrible mistake has been made. Saxton is joined by the gang’s misfit crew—Gene O'Donnell as Skinny, Jimmy O'Gatty as Tubby, and Barbara Pepper as Dotty—who mistake Horace for Duke in disguise. Horace races through the confusion and escapes into the street, only to be arrested for indecency and brought back to the hotel.
Millie and Horace are snatched again, coerced into a car, and dragged toward an uncertain fate. The couple dodges their pursuers and hides in a nearby movie theater, catching the tail end of a screening and even winning a prize on stage. But the danger isn’t over. Dotty re-enters the fray, and the gang ties and gags the couple, dragging them deeper into the trap they’ve fallen into.
In a last bid for attention, Horace cranks up the hotel’s radio, and the oddly realistic noises draw frightened neighbors and, eventually, the police. The authorities arrive, rescuing the couple and returning them to their hotel room amid a frenzy of mistaken peril. The audience learns the grim truth: Duke Keesler’s body was stuffed into a closet, and the gang’s stash of money—fifty thousand dollars—secretly tucked away in Horace’s robe pocket becomes the last clue that exposes the crime.
Frankie Saxton and his gang are hauled off to jail, and the newly minted domestic peace of Horace and Millie seems secure—if only for a moment. They’re finally alone in their room, savoring a fragile calm before the inevitable 6 AM wake-up call and the need to check out, signaling the end of their wild first night in the city.
