December 21st 1944,
German Army Group North has been trapped on the Courland Peninsula since mid October. The Soviets have since launched 2 failed attempts to destroy or dimminish the pocket. This will be the third.
Historically this attempt also failed and the offensive was called off within a week. Two more large scale attacks were made before hostilities ended - both ended as further failures. Army Group North (renamed 'Kurland' in mid January) surrendered to Soviet forces on the 7-8th May 1945.