Valerie Edwards sends Daniel Miller and Robert Kirsch on an urgent mission, where they meet renegade CIA Officer Rafael Torres, and uncover signs of a covert invasion.

Berlin Station follows up on the evidence Kirsch brought home from his mission, crystallizing their theory about a possible upcoming invasion.

The Station enlists Rafael Torres to track down a missing comrade's, Daniel Miller's last known location, leading him to hostile territory. Kirsch visits an old friend.

Kirsch and Torres must risk their lives to secure their fallen comrade's location. When B.B. Yates returns to Berlin, the Station must decide whether or not they can trust an emissary of the Oval Office.

Valerie and B.B. rally the support of the 14-Eyes, a powerful intelligence collective. Kirsch and April, using Sofia as bait, trap Sergei. Kirsch offers to swap Sergei for Daniel. April comes clean to her asset, securing the tech for U.S. interests. Esther activates Bruno, a German Special Operator, to locate Daniel. Frost introduces Torres to Hector, whose new identity as a roofer to oligarchs provides a way to infiltrate the Russian elite. Frost investigates one of the soldiers formerly under Krik's command to gain kompromat from his war days.

Valerie is stunned when B.B. betrays her and votes against the 14-Eyes invoking Article 5. April faces the loss of the tech when her assets are arrested and face deportation. Kirsch's spy swap goes horribly awry when Bruno, Esther's officer, is exchanged instead of Daniel. Platov invites Hector and Torres to Krik's dacha, forcing them to navigate the treacherous world of Russian oligarchs. Their mission is upended when Hector falls out of favor with Krik and finds himself human prey in their evening hunt, along with one other prisoner: Daniel.

Daniel and Hector are being hunted by Vassily Krik. They manage to find shelter in a green house in the woods where a well-kept secret will be revealed.

Frost volunteers with Valerie's reluctant consent to rescue Daniel from Krik's estate. When Daniel confronts Frost about his past alias as "Diver" shots are fired. Hector is a secret witness. Krik is arrested by his government. Daniel's body is dumped on the streets of Berlin. Torres uses his cover as a ruse to get Platov to Germany. The Estonian communications network is hijacked, but Sofia can only use her master password by returning to her country.

Mere hours remain before enemy forces topple the Estonian government. Without Langley's backing, Berlin Station acts alone in one final desperate push to prevent the fall of a nation.