We look back at the Cold War and see it as an inevitable outcome of the Second World War, however, as the 1943 section of Seventeen Moments in Soviet History: The Strange Alliance goes to show us, the truth behind the origins of the Cold War would have seemed like a far-fetched theory during the bloody years of the global conflict. Not only did the major world leaders of the Allied Forces meet and communicate on a great level, they also worked together in means that those within the Soviet Union and those within the Western world in later decades would rarely guess could happen. The British for example, signed a Twenty-Year Mutual Assistance Agreement in 1942 to help with the idea that they would “undertake to afford one another military and other assistance and support of all kinds in war against Germany and all those States which are associated with her acts of aggression in Europe.” This blatant protection of one another from the powers of Germany shows how desperate not only the British Isles were, but the Soviets as well, even with the sheer numbers they had to hold off German occupation and destruction. Through this an unexpected ally was certainly created! A joint bond between East and West, two different spheres of the world which have always conflicted or not trusted one another joined by a common enemy.

W. S. Churchill, F. D. Roosevelt and I. V. Stalin at the conference of Yalta in February 1945
Source: FUNET Image Archive. 1997.
The odd alliance didn’t end at the beginning of the Atlantic and exclude the British “spin-off” of America, who also participated in a set of help with the Lend-Lease Agreement between the Soviet Union and the United States in 1942 which gave the Soviet Union as many resources that the United States could afford to send out with very little obligation of repayment until the end of the war to help supply an ideologically different nation. These two creations truly show how desperate both sides of the world were in the destruction of the German Empire and its constant aggression against almost every other faction of the world. A question I constantly consider behind the magic of this alliance, though short lived, is what sort of conditions would be needed to be created in order to ally the two spheres of the World? If anything, hypothesizing on this creates some great alternative history scenarios!
Sources:
Seventeen moments links: http://www.soviethistory.org/index.php?page=subject&SubjectID=1943alliance&Year=1943