This is the story of the highest battlefield of World War Two, which brings to life the extremes endured during this harsh mountain warfare. When the German war machine began faltering from a shortage of oil after the failed Blitzkrieg against the Soviet Union, the Wehrmacht launched Operation Edelweiss in the summer of 1942, a bold attempt to capture the Soviet oilfields of Grozny and Baku and open the way to securing the vast reserves of Middle Eastern oil. Hitler viewed this campaign as the key to victory in World War Two. Mountain warfare requires unique skills: climbing and survival techniques, unconventional logistical and medical arrangements and knowledge of ballistics at high altitudes. The Main Caucasus Ridge became the battleground that saw the elite German mountain divisions clash with the untrained soldiers of the Red Army, as they fought each other, the weather and the terrain.