The City is an Engine. He just found the key. Heller Wilson, a brilliant mathematics student, needs one revolutionary idea to complete his thesis. Just one. To find it, he's tracked down Dr. Spencer Brownfield, once the most promising mind of his generation. These days, he's still a genius, but also quite possibly insane; he claims he's been secretly controlling the entire city for decades through complex applications of the Butterfly Effect. Even worse: Spencer refuses to give up a single theorem until Heller signs on as his apprentice. Bad things are coming, he believes, and someone has to keep New York safe after he's gone. Quite possibly insane--but quite possibly not.