What is the main conflict in Pale Fire by Vladimir Nabokov?

To initial appearances, Pale Fire is the final, unfinished poem by renowned poet John Shade, with a forward and commentary by fellow university instructor Charles Kinbote. However, through the commentary, this novel becomes the story Charles Kinbote longs to tell, the story of Charles X, the exiled, beloved king of Zembla. Kinbote proves himself an unreliable narrator, and the reader must attempt to discern the layers of illusive truth behind the tale.