Mike helps a minister find his runaway teenage daughter who was lured to Philadelphia by an online child predator.

Mike comes to regret helping a gambler who owes money to a bookie; Marcellus requests his old partner's assistance in apprehending a suspected killer.

Mike comes to the aid of the wife and daughter of a cop who are fleeing the violence of their home, and finds them temporary refuge at Saint Victor's. After Grizz tells the wife that Mike's a former cop, she flees to New Jersey where Mike quickly tracks her down. Upon their return to Philly, Marcellus arrests them for kidnapping but is forced to release them when neither one will reveal the whereabouts of the little girl. Marcellus connects Mike with the cop, who tells a story that resonates uncomfortably with Mike's recollection of his own behavior, which is confirmed by his son. Troubled, he talks to Grizz and then follows his advice to make amends with Heather. When Mike sets a trap to discover the truth about the cop's abuse, he finds that the truth is not always what it seems.

Mike's efforts to help his friend Vanessa get her brother Teddy off the streets and off drugs puts all of them in danger after Teddy steals a dope dealer's $15,000 stash. When Mike strikes a bargain to spare their lives in exchange for paying the dealer the wholesale price of the drugs, he discovers that Teddy has stolen all of Vanessa's money, as well as the drugs provided by Marcellus to bust the dealer. Mike is forced to come to the painful realization that going to prison may be Teddy's only salvation.

Mike takes a job chauffeuring loanshark Jack Shannon, but begins to have doubts about the wisdom of doing so after Grizz and Marcellus warn him that he's headed down a slippery slope. After he's goaded into beating up a man to collect on a debt for Shannon, Mike realizes that his friends are right that he's headed for trouble, and tells Shannon he's quitting. Shannon tries to entice him to stay by offering to call in a favor with the District Attorney and have the case which led to Mike's dismissal from the force thrown out. Although he's sorely tempted, Mike turns Shannon down. After Mike leaves, Marcellus appears and is greeted warmly by Shannon.

After Marcellus frames bookie Nick Bennett for smuggling guns and Bennett's wife asks Mike to help clear him, Mike discovers that Jack Shannon is blackmailing Marcellus and using him to extort Bennett. Mike arranges a sit-down between Bennett and Shannon, tricks Shannon into confessing to a crime, and uses the confession which Marcellus has captured on tape to blackmail Shannon into cutting Bennett and Marcellus loose.

When a homeless man dies in his cab, Olshansky sets out to find the man's estranged family.

After Mike picks up Chuck, a frantic naked man, he helps him track down the prostitute who robbed him of his clothes, money, and most importantly, his wedding ring. They find Anna, the prostitute, who tells them that Raymond, her abusive pimp, has taken Chuck's belongings. Sympathetic to her plight, Mike offers to buy Anna's freedom from Raymond in addition to Chuck's wedding ring. After Raymond returns his ring, Chuck decides not to pay the $5000 Raymond wants for Anna, and sets Mike up for arrest. After Grizz bails him out, Mike fights Raymond to help Anna escape. Chuck finally tells the police and his wife the truth. Even though she throws him out, he's determined to win her back. Mike takes Chuck's $5000 and pays off Grizz's debt to a loan shark, which eliminates Grizz's need to ""borrow"" money from the collection plate.

Mike picks up a man who has just been given $10,000 to help an immigrant mother reunite with her lost child. When the fare leaves the money in the backseat of the cab, Mike experiences a night of manic complications trying to return it. He takes a woman in labor to the hospital, and later reunites her with the absent father; his cab is towed; he's hauled in by the police; and he enlists the help of a pair of street hustlers peddling fake Rolexes in an effort to assist a woman who is being blackmailed. When he finally hooks up with his passenger and returns the money, we discover that the man is a con artist who is using the money to play high-stakes poker.

Olshansky becomes the bodyguard for Abby, a woman terrorized by a stalker that neither she nor anyone else has ever seen. The signature item he leaves is a red rose. After Olshansky and Abby have a tryst, Olshansky tells her it can't continue. The next day, someone shoots at Olshansky -- is it the stalker, or is it Abby, and the stalker is a figment of her imagination?

Mike helps a Department of Justice employee whose sister has been kidnapped by a hitman who wants information about a banker in the Witness Protection Program who is scheduled to testify against the drug dealer whose money he laundered.

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.

Mike Jr. is upset when he sees a copy of his parents' divorce decree and gets into the sacramental wine at St. Vincent's, leading Mike to realize the importance of spending more time with his son; Grizz's high school sweetheart comes back into his life when she divorces her husband and comes to work at the parish; the cop who arrested Mike is mounting a case against Marcellus and asks Mike to flip on his former partner; when the cop's son is murdered during a robbery, Marcellus is assigned the case, which goes cold when the only witness is murdered; Mike and Marcellus join forces to find the cop before he administers some street justice to his son's killer; Marcellus offers to help his nemesis cover up his execution of the killer, but the cop declines and turns himself in, giving Marcellus a chance to get out from under his corrupt behavior.

Heather, Mikey and Grizz keep vigil as Marcellus and the rest of the force hunt down Johnny Scanlon, who has kidnapped Mike and threatens to execute him at the exact same as Johnny's brother Jimmy is executed by the state because Mike precipitated the incident many years before which led to Jimmy's killing a cop.

Romantic feelings resurface between Olshansky and his high school girlfriend as he reconnects with her while trying to help her schizophrenic sister.

A burglar that Mike once put in jail fears a third strike conviction if he reports that he witnessed a murder as he lay in wait to rob an office, and he goes to Mike for help in convincing the police that the wrong man has been arrested for the crime. The detective on the case has a long-standing grudge against Mike, so he does an end run around her by enlisting Marcellus's help. When they discover that the perp is an undercover cop, they are forced to devise a plan to trap him into confessing.

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

After Mike convinces Marcellus to help him work to free a man they incorrectly helped send to prison, he incurs the further wrath of his father; Mike has mixed feelings when he discovers that Heather is seriously dating Ryan, who begins to provide Mikey with perks that are way out of Mike's league; Grizz assures Mike of his son's love, and Mikey confirms that for his father.

After Bill Olshansky has heart attack which creates irreversible and uncurable heart damage, Mike's decision to take care of his father leads them over rough territory as they hash out old grievances and can't seem to connect; in an attempt to get them to reconcile, Faith provides some words of wisdom for both father and son which finally enables them to bridge the gulf that separates them before Bill dies; picking up on Mike's feelings about Ryan, Mikey begins acting out towards the new man in his mother's life; Grizz is suspended by the bishop after $2,000 is missing from the collection money; Mike enlists the help of Aldo and the altar boys in exposing the real thief; Grizz contemplates leaving the priesthood in the face of his growing attraction to Beth, coupled with the bishop's lack of confidence and support.