Danny and Jackie's investigation of a case involving domestic violence lead them to a high-powered city councilman. Subsequently, Danny is taken hostage after a man from his past who is bent on revenge is released from prison. Frank talks a rookie officer out of suicide and, in another instance, makes a commitment to a man to find his mother's killer. In their personal lives, Danny is concerned over Linda's new job at the hospital. Frank, meanwhile, raises questions over Henry's questionable driving and memory problems, and Erin faces off against her ex-husband in court.