On November 20, 1941, the Japanese Navy's submarine force headed for Pearl Harbor as the advance dispatch of the Combined Fleet. Led by the submarine tender with flagship Katori in the lead, the elite of the I-go march on. Far behind them was a small extra submarine moving like a dolphin. It's a German-made U-boat. A great success by the 16 “Donkame bastards”! The day of the attack on Pearl Harbor is coming soon!