What is the main conflict in Thursday Next in Something Rotten: A Novel by Jasper Fforde?

Something Rotten is a humorous fiction about a reality that shifts among absurdities in real life, fiction, and the space between the living and dead. The fictional reality known as Book World contains both characters from stories and living human beings from real life. The fictional characters can also enter real life and interact with humans. Crazy time travel plays another important role in the story.