FSB major Natalia Rostova receives a note listing jewels stolen by the Germans from Smolensk during World War II. Particular interest is drawn to an ancient Sumerian symbol and the number of a German submarine. Rostova is sent to the Laptev Sea, where they find a rescue raft with the body of a German submariner who has recently died. This leads her to the solution of mystical secrets and mysteries from the time of the Third Reich.