Watch Soap2Day. The year is 1944, Atze and Samuel occasionally operate on the black market, but mostly keep quiet and wait for the Americans to come. When the last German submarine, the U-900, is sent on a final mission, Atze foolishly messes with the general of this mission and has to go undercover. Together with his friend Samuel and the actress Maria, who disguises herself as a man for this purpose, he therefore smuggles himself onto the U-900 and pretends to be the captain. Since he has no idea about seafaring and gives increasingly strange orders, the crew soon becomes suspicious.