Marcellus gets a new partner, Aldo Rossi, and Mike has trouble adjusting to the change; after initially resisting Heather's suggestion that he reconcile with his father on his upcoming birthday, Mike finally relents, but his father rejects both his present and Mike; the ""Inquirer"" reporter who wrote the story of Mike's arrest now wants to paint him as a hero, much to Mike's disgust; when his friend Doug is killed in a hit-and-run accident after he gets out of his cab, Mike promises Doug's son Bobby that he will find the man who killed his father; after finding out that Doug had uncovered a fraudulent scheme at his company, Mike suspects that the company's chief financial officer had a hand in his death, and has mixed feelings when he is proved wrong by Rossi, who uncovers the real culprit.

An exhausted E.R. doctor's error results in a man's death, and an upset Heather seeks Mike's help when the hospital administration refuses to take action after she reveals that the doctor falsified the man's chart to cover up his mistake; Mike convinces a reluctant Heather to give the story to reporter Emily Carson, whose investigation results in Heather's being fired and blacklisted on a trumped-up charge; Mike's concern that Heather may have to move far from Philadelphia with Mikey to find work puts a strain on his budding relationship with Faith, who begins to doubt that Mike is over Heather; Mike enlists the help of Ryan Ambrose, a psychiatrist at the hospital who supports Heather, in obtaining information that convinces the E.R. doctor to back up Heather's account of the patient's death and to admit his mistakes to Emily; Heather is reinstated, and she and Mike realize that it's over after spending the night together, leaving Mike free to commit himself to a relationship with Fait