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.