A luxury liner departs America for the shores of Europe, which is in the throes of war. The passengers, of different nationalities, include wealthy businessmen, actresses, stalwart silk boys, artists, ordinary teachers and secret agents of countries preparing for war. At the beginning of the voyage, the captain cuts the ship off from the outside world.
On 26th of August 1939 the Oceania steamboat leaves the New York harbour with the ex-spy Maria Holm on board. Now she is the owner of a dressmaker's showroom, but for just one last time is taking important documents to Europe for the sake of peace.