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.

The explosion of a fishing boat is detected. CIA agent Rafael Torres violates the order of the Station Chief of Berlin Station, and retrieves the burned body that he believes is of missing CIA agent Daniel Miller.

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.

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.