In Yuri's Revenge, the Allies are celebrating their victory over the Soviet Union in the previous game. However, Yuri escaped both the Soviets and Allies and formed a secret army of his own, drawing heavily on telepathic abilities and genetic manipulation. He then constructed a network of mind controlling Psychic Dominators all across the world in order to control the entire planet all at once. He activated the network and started turning the world's population into mindless slaves. At the last minute, an air strike ordered by the President of the United States Michael Dugan barely manages to damage the nuclear plant powering the device in San Francisco, saving the United States military command from falling under Yuri's control.
The expansion includes NEW units,buldings and specially a new army (Yuris Army) http://en.wikipedia.org/wiki/Command_&...i's_Revenge
