What is the main conflict in The Silence of the Lambs by Thomas Harris?

Starling is plucked out of the FBI Academy by her mentor, Jack Crawford, to track down Buffalo Bill before he kills again. The novel takes Clarice on a journey from Lecter's dank cell in the bowels of the Baltimore State Hospital for the Criminally Insane to the slab where Buffalo Bill's latest body lies. The pressure intensifies when Bill kidnaps the daughter of U.S. Senator Ruth Martin.