It is 1949, and Mao Zedong, leader of the Communist Party of China, has just won the long and bloody civil war for control of China through the backing of the USSR. He will be transforming China into a communist country like the USSR and views Stalin in high regards as leader of global communism and world revolution.
Now 1950, China and the USSR meet and sign on the 30 Year Treaty of Friendship, Alliance and Mutual Assistence. This treaty established the formal connection between these two countries and the USSR began to support China economically with industrialization and military buildup; Robert Farley in his article covering this topic, goes as far as saying these financial contributions from the USSR, at one point accounted for 7% of China's economy in the 50s.
October, 1950, the Sino-Soviet alliance has decided to enter the Korean war. The plan is for 2 million Chinese troops to fight on the side of the North Koreans against the United Nations troops. The USSR does not want to use their own troops which would escalate the war with the western powers but will supply material support for China. Mao Zedong agrees with this to uphold Soviet-Sino alliance, to protect Chinese borders, and to assert China as a world power.
However, 400,000 Chinese deaths later, the war ends in stalemate on July 27, 1953. Mao Zedong beleived that there was unequal burden sharing during this conflict and was unhappy with the withdrawl and "betrayal" of promised soviet air support which led to many Chinese casualties. Between Mao and the leaders of the USSR, a crack had began to form in the foundation of trust in their alliance.