In December 1941, the cold wind carried snow particles and slapped the trenches on the outskirts of Moscow. Li Mo opened his eyes suddenly, the pungent smell of gunpowder smoke rushed straight into his nose, and the sound of gunfire and the roar of soldiers could be heard in his ears. He looked down at the shabby Soviet military uniform on his body, with a bleeding bandage still wrapped around his chest, and a mechanical voice suddenly sounded in his mind: "Ding! Welcome to bind to the 'World War II Counterattack System'. It was detected that the host was on the battlefield of the Moscow Defense War, and his current identity was a second-class soldier of the Soviet Red Army. Main mission: Assist the Soviet army to hold the defense line for 72 hours. Rewards: Modern assault rifle design drawings and basic military command courses.