Westerplatte, August 31, 1939, the last day and night before the outbreak of war. The firing posts are on alert, because the German battleship Schlezwig Holstein, who came on a courtesy visit, is moored in the port. On the morning of September 1, a German mine explodes at the guardhouse wall. An unequal fight begins. According to the assumptions, the Polish ammunition depot is to defend itself for twelve hours.