Sam Waterston joins the cast for a fifth season of the acclaimed series as Assistant District Attorney Jack McCoy in a story line that has Ben Stone quitting in disgust after a witness he vowed to protect is murdered. The talented but womanizing McCoy works with colleague Claire Kincade (Jill Hennessy) to put away the criminals collared by detectives Briscoe (Jerry Orbach) and Logan (Chris Noth). S. Epatha Merkerson also stars.