A plane crash in the Ural Mountains sends Tom and Nez to Russia on a covert operation to infiltrate a mysterious, top-secret military facility. Scottie enlists Mr. Solomon to find answers about her husband.

When ruthless terrorists escape from a "black site'' prison in Manhattan, Tom and the Halycon team must lock down the city and find the terrorists before disaster strikes.

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.

In the explosive season finale, 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.