Sta dihtya tis arahnis (1973)

Professor Algeras becomes the target of foreign agents of great powers, who, using every legitimate and unfair means, are trying to become holders of his scientific discovery. The toughest and ruthless foreign agent, who finally traps Algeria, comes from the countries of the curtain, Milko. Eventually it turns out that Milko, who has been brainwashed, was the lone son of the professor since the Communist childhood.