The book begins with a strained friendship. It seems our unnamed narrator's friend, Tyler Durden, has a gun in his mouth. They talk (as well as one can talk with a gun in his mouth) about guns, explosives, destruction.
They're on the top floor of a building, and the Mischief Committee of Project Mayhem (whatever that is) is below, pushing desks and filing cabinets out of windows. Any minute now, the Parker Morris building will be demolished, with Tyler and our narrator inside it.
How did they get to this point? Our narrator says, "I remember everything." (1.44)