As Danny and Lexi finish tracking down the last of Farouk's black market antiquities, they begin to make plans for their future. But their plans are derailed when the Vatican is attacked by terrorists. A person from Danny's past returns, leading them on a new hunt to recover one of the greatest lost treasures of Asia, the Spirit Banner of Genghis Khan.

A visit with Simon in prison yields new information on the Spirit Banner's last whereabouts, sending the team to Russia.

Danny and Lexi join forces with Levchenko's gang as they journey to Mongolia. Levchenko hopes to find the Spirit Banner for himself, even with the Great Khan's horde in hot pursuit.

Danny enlists his estranged father, Patrick, in their quest for the Spirit Banner. Patrick leads them to a secret base in Laos, where he makes a startling admission to Lexi about the secret he's hiding from his son.

After crash-landing in the jungles of Laos, Lexi is gravely injured, leaving Danny and Patrick in a rush to find refuge. Meanwhile, Chuck uncovers new information on the relationship between the Vatican and the CIA.

While their team gets closer to unlocking the location of the Spirit Banner, Danny is forced to pick sides between Lexi and Kate.

The recovered scroll's translation takes Danny, Lexi, Kate and Violet to the snowy tundra of Mongolia, with deadly results.