A smuggler carrying gold coins on a motor vessel throws overboard a mechanic who saw the secret cargo. In the port of Leningrad, a young customs officer, whose friend works on the ship as a doctor, is sent to inspect the ship. The assassin puts the gold in the doctor's luggage and the customs officer lets his friend through without examination. The smuggler arrives at the doctor's house and takes the gold, threatening to hold the doctor responsible. The new customs officer will have to unravel these mysterious events.
