Jason Ty Hardin is handcuffed and flown into Athens airport, where Inspector Starkis Ferdinando Poggi waits. Jason escapes, unaware that Bulgarian Demetrius Remo De Angelis is secretly helping him. While hunting for his ally Pizza Vittorio Caprioli at the Gold Star club, Jason is kidnapped by Demetrius, photographed beside a dead woman, and blackmailed into working for him. He infiltrates a prison and extracts a tooth from a corpse, a move that will bind many sides to their fates. He then double-crosses Demetrius and takes refuge in a bar, where he phones Pizza, only to discover the call is bugged by both the police and a mysterious Albanian Gordon Mitchell who sends two gunmen to kill him. Jason escapes, and the gunmen are shot by the police, but the net tightens around him.
Major Worthington Clark Michael Rennie, a British agent collaborating with the local police, teams up with his colleague Lloyd Giulio Coltellacci to keep tabs on Jason’s movements. Jason arranges a meet with Pizza, yet is intercepted by the Albanian and his henchmen, who are in turn attacked by Demetrius and the police. A furious gunfight erupts, leaving several henchmen dead.
Jason finally makes contact with Pizza and hands him the tooth for safekeeping, asking Pizza to also fabricate a fake tooth. He is advised to reach a Parthenon tour guide, but the informant is killed by the Albanian, who then gives chase through the city. The police attempt to trap Jason by retracting a bridge, but he makes the leap while the Albanian must swim to safety.
At the Acropolis, Jason meets Greta Paola Pitagora, the tour guide whom the photograph suggests is dead. The Albanian arrives and threatens them both, but Jason manages to hand over the fake tooth and disarm the Albanian, allowing him and Greta to slip away. Back at the Gold Star club, Jason tries to recruit Pizza for a scheme to profit from the chaos among the various chasing factions; Pizza declines, but dancer Rumba Graziella Granata agrees to act as their go-between.
Jason sees Greta after work and convinces her to drive him to the disused factory he uses as a hideout. Greta reveals she was forced to work for Demetrius to secure her sister’s child’s release from behind the Iron Curtain; the sister had been connected to a Bulgarian agent who brought valuable information—information tied to the dead man whose tooth everyone is pursuing. Jason agrees to give Greta the tooth so she can swap it for her niece’s freedom.
While driving away, Greta is tailed by the Albanian, who tortures and kills her. Jason tries to orchestrate a ransom through Rumba to obtain the tooth from Pizza, but Rumba instead informs Demetrius’s henchman, whom she’s secretly working for. Suspicious, Jason goes to Rumba’s room, only for Demetrius and his men to arrive as well. In the ensuing fight, Jason is wounded, while Demetrius, his henchmen, and Rumba are killed. Major Clark saves Jason by killing a henchman and reveals that the tooth contains a microfilm with a list of double agents—he offers Jason money and a new passport in exchange for the tooth.
Jason heads to the club to retrieve the tooth, only to find the Albanian has abducted Pizza. Starkis arrives, but Jason escapes and steals a police car, guiding Clark to the factory where the Albanian is torturing Pizza. Jason enters the factory, kills the Albanian and his henchmen, and rescues Pizza, who reveals the tooth has been hidden inside Jason’s keyring the entire time. Clark steals the keyring and hands Jason over to Starkis, who promptly tries to take him into custody. Jason escapes again, hides in Clark’s car, and forces him to return the tooth.
In negotiations with Clark and Lloyd, Jason demands 40,000 dollars, a passport, and Greta’s niece’s release. He hints that the communists might swap the child for a spy and then reveals he knows Clark to be a double agent working for the Russians. Lloyd agrees to the deal and the exchange takes place, while Clark admits he copied the microfilm, ensuring both sides can access the names. Jason hands the child to Pizza before Starkis arrives and arrests him, though Jason escapes once more. The chase continues, with every faction maneuvering to secure the dangerous microfilm—and Jason remains one step ahead, driven by a mix of survival and the uneasy promise of a hidden truth embedded in a tiny, unassuming tooth.
