British film director Derek Engles recognises Neil Blair, an extra on his set, as he prepares to shoot a scene, and pulls him aside for a private talk. To investigate intelligence he has picked up in Italy, Engles offers Blair a job, drawing on their past relationship since Blair used to be his commanding officer. Blair accepts, and travels to the Italian Alps to inform on the habits of everyone staying at a ski lodge, while posing as a scriptwriter.
There he meets Joe Wesson, the cameraman who is part of a setup that pretends they’re making a film, though Wesson is unaware that no real project exists. A hotel in the valley points them toward a mountain-top lodge, where they push their way upstairs to find rooms. At the top, Aldo, the innkeeper, refuses them, and Blair and Wesson press on. They encounter Stefano Valdini, staying as a guest, who helps them navigate the language barrier and secure rooms. Back in the bar, another man claims he has booked a room too, but Aldo has said none are available; Wesson instructs him to go upstairs and claim an unoccupied room at the corridor’s end. Later that man introduces himself as Gilbert Mayne.
Blair’s investigations soon bring him into contact with Carla Rometta, known as the Comtessa Forelli, who Blair believes he has met before in Naples, though she denies it. A Greek named Von Kellerman arrives as well, and Blair senses a tense, layered intrigue. Kellerman, who is more deeply connected to the shadowy plot, speaks with a level of German that Blair, who has some German, can roughly understand.
Blair’s first report catches Engles’ eye because the lodge is to be auctioned the next day. A local hotel proprietor cautions that the auction is rigged in someone’s favor, but the bidding becomes heated, with a lawyer for an unknown party driving an outsized win. Von Kellerman’s presence intensifies the mystery, as Blair learns that the situation at the lodge is far from a simple film shoot.
Von Kellerman, the Gestapo agent, reveals a broader plan: during the war Italy’s gold reserves were to be moved to Germany, a task he had assigned to Captain Stelben. Stelben is involved with Carla Rometta, and at Carla’s urging, Stelben leaves the gold at the lodge. After firing on his own men, Stelben claims he’s been ambushed. Kellerman then discovers the gold’s location and intends to use it to finance a rebuilt fascist Germany.
Carla’s loyalty becomes central to the tension as she warns Mayne, who has paid a staggering 4.5 million lira to purchase the lodge at auction, that he intends to kill Valdini and others. In the confrontation, Mayne shoots Valdini dead, and Aldo, following Kellerman’s orders, knifes Mayne in the back. Kellerman produces a pistol, locks Carla away, and orders the Englishmen to dig for the gold in the cellar.
Mayne regains consciousness, tries to free Carla, and accidentally starts a blaze by knocking over a lamp. The lodge catches fire, and Mayne dies in the flames. With no gold found, Kellerman suspects Engles knows where it is and shoots him. In the ensuing struggle, Joe Wesson drags the unconscious Blair out of the basement as the flames roar and the building collapses around them. Carla, cradling Blair, reveals that she knows where the gold lies but will never disclose its location, acknowledging that it has caused too many deaths.
