On the run from the police in Athens, a man named Jason has in his possession a microfilm eagerly sought by both criminal gangs and government agencies.
Bob Terry is in love with Lois Borden the daughter of his employer, John Borden. When some bonds are missing from the office, Bob is accused and because of Borden's strong sense of obligation to his stockholders, Bob is railroaded to prison. A few years later, the real thief is apprehended and Bob is released. He now begins his plan for revenge against Borden with the aid of his prison cell mate Todd and a gangster, John Carmody. Soon, some bonds are missing again and Borden knows Bob is involved but because Bob has suffered at his hands before, Borden assumes the responsibility and is about to be sentenced to prison. Todd is shot while trying to steal the bonds back from Carmody, but gets the bonds back to Bob and, before he dies, begs Bob to return them to the owner.
Betrayed and on the run, a former North Korean agent tries to seek revenge on the man who killed his wife, find his missing daughter, and uncover the secrets hidden inside the eyeglasses of a dead man.
An RCMP officer is ordered to discreetly take a Russian immigrant into custody in advance of a state visit by the Soviet premier. When the prisoner is kidnapped, the officer is drawn into a complicated assassination scheme.
A couple vacationing in Morocco with their young son accidentally stumble upon an assassination plot. When the child is kidnapped to ensure their silence, they have to take matters into their own hands to save him.
A paranoid, secretive surveillance expert has a crisis of conscience when he suspects that the couple he is spying on will be murdered.
Set 3 years after the first season, members of the National Security Service (NSS) team, including Jung Yoo Gun, Ji Soo Yeon and other agents attempt to pull the curtain on mysterious group IRIS. Agent Yoo Gun is the leader of the NSS TF-A team. While he goes up against Baek San, Yoo Gun becomes involved in a case which changes his fate forever.
Colonel Stok, a Soviet intelligence officer responsible for security at the Berlin Wall, appears to want to defect but the evidence is contradictory. Stok wants the British to handle his defection and asks for one of their agents, Harry Palmer, to smuggle him out of East Germany.
Khalid, entrusted with the task of eliminating former soldier turned rogue Kabir, engages in an epic battle with his mentor who taught him everything.
After three British agents are assigned to assassinate a mysterious German spy during World War I, two of them become ambivalent when their duty to the mission conflicts with their consciences.
Edward Wilson, the only witness to his father's suicide and member of the Skull and Bones Society while a student at Yale, is a morally upright young man who values honor and discretion, qualities that help him to be recruited for a career in the newly founded OSS. His dedication to his work does not come without a price though, leading him to sacrifice his ideals and eventually his family.