In 1929, a freight train traveling from the Soviet Union is hijacked. Meanwhile, Chief Inspector Gereon Rath from Cologne pursues a mission in Berlin.

While interrogating König, Rath loses control of the situation. Charlotte moonlights to make ends meet. An alter ego commits a betrayal.

The freight train arrives in Berlin. Tempers explode in Charlotte's household. Aspiring inspector Jänicke makes use of a surprising skill.

At the May Day protest, police action spirals out of control. A body is found in a canal. An unsuspecting Svetlana returns to her apartment.

Kardakow realizes his first instinct was correct. A photo enlargement yields two leads. Rath and Charlotte get key intel from a colorful character.

Rath confesses to a priest -- and later to Wolter. Charlotte charms medical student Rudi into performing a secret autopsy, which uncovers a vital clue.

Rath's pharmacist gets shady instructions. Rath learns who's behind the train smuggling operation and why, and recalls the last time he saw his brother.

Greta goes on a romantic outing with Fritz. Krajewski finally reveals where the film is hidden. A new patient is brought to Dr. Schmidt for treatment.

A mass grave is found in the woods. Charlotte's sister Toni makes a troubling discovery. A meeting with Homicide leads Rath to a dreadful realization.

Jänicke spots a match that leads to two suspects in the Red Fortress massacre. Blackmail and bribes fuel a Soviet-German tug-of-war over the train.

Trochin transacts his deal with Benda. Moritz snoops in Wolter's cellar. Rath and photographer Gräf gather proof of a secret air force base in Lipetsk.

The ballistics report in a police officer's murder casts suspicion on two colleagues. While her employers are out, Greta steals a moment with Fritz.

Greta witnesses a horrifying scene. In police custody, the Black Reichswehr leaders are visited by a collaborator. Charlotte fights for survival.

A radio announcement makes Rath realize what the Black Reichswehr is planning. Charlotte stumbles upon a find that she hopes will save her life.

Defying Benda's orders, Rath and Charlotte race to intercept the train. Helga speaks her mind at a memorial. Greta participates in a vengeful plot.

Greatly outnumbered, Rath, Henning and Czerwinski use their wits to fight their foes. Svetlana is tracked down. Dr. Schmidt forces a truth to be seen.