Opening scene shows German sailors gathered around two naval officers on a dock. One is in a dark uniform with dark hat. The other is in working uniform and a white hat. He renders traditional hand salute. View from further away shows many sailors and a couple of officers crowded together on a wooden pier, and shifts to reveal sailors lined up formally on the deck of a submarine tied to the pier. Sailors are gathered informally on the deck of another submarine in the background. A closeup from below shows officers saluting from the bridge of the first submarine. Sailors wave their hats from a pier next to a large docked ship, as the submarine sails away into the harbor. Change of scene shows submarine cruising on the surface passing a camera on another boat (unseen). Views of a surface warship with sun in background obscured by mist. Submarine seen submerging. Closeup of sailor using a signal lamp on a submarine. A submarine and surface warship signalling each other with lamps. A submarine cruising on the surface is passed by a warplane at low altitude. Scene shifts again to two submarines cruising on the surface side by side. Glimpses of wakes churned up from some surface vessels.