Hitler's plan began to take form and work in August. The Russians, led by Zhukov, were severely outmatched and the Germans captured 90% of the city. The Soviets were ordered never to surrender, and held their part of the city for many months until the harsh winter came. The unprepared Germans,who invaded in June, could not withstand the cold and their materials were not adiquit for sub-zero temperatures. The Soviets then launched a counterattack which drove the Nazis back, eventually leading to their retreat on January 31, 1943.