A new detective joins the crew, a relationship heads to a new road, and death takes its ugly toll on two of the detectives. Jonathan LaPaglia joins the cast as Detective Tommy MacNamara, an Irish cop with a know-it-all attitude and a distinctive personality, which doesn't go well with the team, especially J.C. Unfortunately, he was only able to shine his talents for a short while due to his murder. Eddie and Nina go through many obstacles in their relationship, especially when Nina is trying to recover from a gun shot wound she got last season. Eddie is determined to make it last and asks Nina to marry him, which she accepts. However, in order to make that happen, Nina must divorce her first husband. Nina is also going through the process of trying to get her daughter, whom she gave up for adoption, back into her life. While dealing with that, for a while she starts to question her future as a cop. While Eddie is learning of these new secrets about Nina, he deals with his father's death (or suicide), and unfortunately meets an untimely death. As for Lt. Cooper, she starts an elicit affair with a captain and goes through a rocky separation from her husband and family.