This is an alternative history scenario, when you lead the reinforced remnants of Army Group "Center" against overextended elements of the Red Army near river Vistula. In a way this is what hypothetically could have happened if Germans decided to launch their autumn-1944 counteroffensive in the east rather than in the west. "Wacht am Weichsel" is fictional and hypothetical mix of historical operations "Zitadel" and "Wacht am Rhein".
The situation on the frontline is somewhat resembling the one from August 1944. The Soviets crossed river Vistula in force north of Kraków, but their supply lines are overextended. This is the most important factor that makes this scenario winnable, as you will have to strike at the Red Army while being heavily outnumbered. Not many resources are left for you to use. You will be able to call a limited number of airstrikes and run a few air-supply missions. You will recieve some reinforcements in later turns, but nothing comparable to what the enemy will be given (an illustration of Soviet industrial advantage late in the war). You will also have to create proper logistics of your own, as your lines are cut and some of your units are in dissaray because of the russian offensive.
Speed is of the essence. Soviet reinforcements will be coming from all sides, so you will have to leave some reserves to protect your flanks east of Vistula. After approximately 2 months (14 turns) Moscow will not only realize your operational plans, but will also gather enough forces to launch a counter-offensive of their own and at that point the operation will be over. Enemy divisions will start arriving at turn 4. But if you succeed, you will inflict massive casualties upon the enemy and move the frontline some 500 kilometers east.
Hard challenge is awaiting you, good luck!
Initial disposition of forces:
Axis: 540 tanks and assault guns, 468 000 men.
Soviets: 1 980 tanks and assault guns, 825 000 men.