A routine trip to New York turns dangerous when ex-operative Tom Keen is recruited by Scottie Hargrave, the head of an international security firm, to help rescue a kidnapped CIA agent. During the mission, Tom discovers evidence of a conspiracy within his own family.

When an American journalist and close family friend of Scottie is falsely arrested for espionage in a dangerous foreign country, the Halcyon team mounts a last-ditch effort to rescue him before time runs out.

After a plane crashes in the Ural Mountains, Tom and Nez go undercover in Russia to infiltrate a mysterious, top-secret military facility. Meanwhile, Scottie enlists Mr. Solomon to find answers about her husband.

When ruthless terrorists escape from a secret black site prison in Manhattan, Tom and the Halycon team must lock down the city and find them before disaster strikes. Meanwhile, Scottie uncovers clues about her late husband that could expose Tom's identity.

On the hunt for a ring of ruthless thieves who steal classified material, Tom and Mattias must go undercover on an international flight they believe will be hijacked. Howard urges Tom to find proof of a conspiracy orchestrated by Scottie.

When a wealthy businessman, his wife and young son are abducted by professional kidnappers, the Halcyon team is tasked to get the family back. But with time running out, the team must make a dangerous choice. Meanwhile, Tom risks exposure to save Howard from Scottie.

Tensions escalate between Scottie and Howard forcing Tom to reach out to an unexpected ally for help. As explosive family secrets come to light, Tom races against time to learn the truth about Whitehall.

Scottie and Howard battle for control of Halcyon and the dangerous technology tied to Whitehall. Tom clashes with Mr. Solomon as he makes a fateful choice.