What is the conflict of the book The Client ?

The novel's main conflict is centered around Mark, a streetwise eleven-year-old, and his younger brother, Ricky, who witness the suicide of New Orleans mafia lawyer, Jerome Clifford. Mark and Ricky flee the scene, but the trauma of the experience sends Ricky into severe shock. Just before Clifford shoots himself, he spills a big mob secret to Mark. Clifford tells Mark the location of Senator Boyette's body, a piece of information the FBI has been desperately trying to uncover, because Senator Boyette was murdered by the notorious mafia man, Barry Muldanno. The FBI and mafia soon learn that Mark knows the location of the senator's body. Mark realizes that if he tells the FBI what he knows, the mafia will be after him and will not stop until they kill him. Mark has seen enough movies to know that the mafia never forgets.