A double murder at a pharmacy leads Washington and Fitch to the homicide of an attorney being investigated by Longford and Mahajan. The team finds that the two seemingly random incidents are connected and as they put the clues together, they are faced with a hostage situation.
Lt. Mason promotes narcotics cop Stone to homicide, and Sanchez is involved in a traffic mishap while pursuing a suspect. Washington is seriously injured just as he is notified that his wife has gone into labor with their first child.
When Calvin Gibbs, a local football hero, is shot to death, Detectives Sanchez and Stone are assigned to the case, where Calvin's older brother Terrence is the prime suspect.
Longford and Mahajan are assigned the case of a groom found dead on his wedding night - pushed overboard the party boat that the rowdy reception was taking place on. Unfortunately, the groom was not very well-liked, and the pair have a long list of suspects to question.
While Washington recuperates in the hospital with his wife and newborn son, Alice Williams, the county Assistant Prosecutor, wants Lt. Mason and Fitch to speak about Washington's shooting to avoid the press having a field day.
Meanwhile, Stone is unnerved at the hard time Fitch is giving him on his first case as a homicide detective.
Fitch, Washington, Longford and Majahan discover that the murder of a squatter who was trying to clean up the community is connected to one of the most powerful men in Detroit.
Stone and Sanchez work the case of a father and his teenage son. While attempting to buy a 1986 Firebird, the teenager is shot dead and his father is beaten but survives, leading the cops to a lethal vintage car scam.
When a woman is shot to death in her SUV, a two-year-old girl is found safely tucked away in the back of the vehicle. This leads Fitch, Washington, Stone & Sanchez on a timely case involving the child care health system. Was the dead woman selling this child, or trying to protect her?
At a college campus, a janitor with a history of drug use is found slashed to death by two co-eds. Longford and Mahajan naturally check out the man's drug connections but eventually discover a motive that startles them both.
While Mahajan is in court, Washington is paired with Longford to investigate the death of a drug dealer known as Toucan, his body found bludgeoned in a garbage can.
This leaves the uneasy Stone and Sanchez to be partnered with Fitch. They're looking for the murderer of a successful female technology executive who was soon to be married.
Unbeknownst to Stone and Sanchez, Fitch overhears his partners discussing their night of passion, which could put a dent in their already fragile 'traingle.'
The discovery of a blood-spattered room sends Fitch, Washington, Stone & Sanchez on a quest to find a missing teen. The teen was a member of a group of friends who were being mentored in the ways of the old Purple Mafia. Drug-smuggling from Canada and severed body parts lead the team to their culprit.
Longford and Majahan take on the case of a man shot dead in the parking lot of a seedy motel. Seems that the man was an out-of-towner competing in a high-stakes poker game, where obviously somebody didn't want him to win.
While a Hollywood production company is filming a movie in Detroit, the drug-riddled starlet of the picture is found murdered in her trailer. Fitch, Longford, Washington & Mahajan interrogate several suspects, including the philandering director, producer and production assistant.
Elsewhere, Stone & Sanchez must figure out how a presumably homeless man's body ended up being frozen in a vacant building. They quickly arrest a vagrant who tries to flee, and he bites Sanchez's arm before Stone can knock him out. As they put the pieces together, they discover that the victim was definitely not homeless, nor poor, but rather well-off.
Stone opens up to Sanchez about his brother's death and his guilt, while Fitch is excited to get a phone call from his son, who wants to come and visit Detroit.
Homicide hits close to home when Alice Williams is found murdered after attending a surprise retirement party for Longford. Mason, a good friend of Alice's, demands justice and this case takes top priority for the team.
All signs point to crooked politician Malloy, whom Alice had dirt on and whom Fitch has always felt was a high-powered criminal. Thanks to a helpful call girl, and her taped confessions of what she knew about Malloy's illegal dealings while being his mistress for a decade, things are looking up. Unfortunately, there's a mole in the department who will do anything to protect Malloy's name and reputation. This leads Fitch on both a professional and personal rampage while Malloy is attending a charity gala.
The team braces for a visit from Special Agent Harkins, who is there to interrogate them about Fitch after Malloy's murder.
Fitch and Washington attend to the case of a missing girl, the granddaughter of a prominent Grosse Pointe man who was found gunned down on a public bus with two other victims. A briefcase with bullet holes and a cell phone help the detectives find out who is responsible and how to get the abducted girl back safely.
Fitch also reveals to Washington exactly why he left his job, wife and son in New York. His excitement over his son visiting him in Detroit is dampened with a phone call from an old associate of his in New York.
A young waitress - the fiance of a Detroit boxer who is poised to earn a lot of money from his next fight - is found beaten to death at a diner. Fitch, Washington, Sanchez and Stone take on the case, and none of them are thrilled that Jess Hawkins will be tagging along and observing their detective work.
Meanwhile, Longford and Mahajan check into the cold case of a man who was murdered five years ago when his mother stops by the precinct with a handful of love letters she had found. They track down the woman he was corresponding with to get some answers.
There's trouble in the workplace when Stone & Sanchez's budding relationship is threatened by the arrival of Riley, a troubled woman from Stone's past.
Longford & Mahajan investigate the murder of a drag queen and delve into the world of The Mother Lode night club to see who would've wanted her dead.
A wounded man enters the precinct, confessing to a gang-related double murder in an alley. The man survives and his story doesn't add up, sending Fitch & Washington to look into the man's criminal history for clues.
Stone's death sends shockwaves through the precinct, most notably for Sanchez, who can't bring herself to go back to work.
Fitch's ex-wife Linda comes to town with their young son Bobby, who has a lot of questions for his Dad as to why he left New York years ago.
The murder of a teenaged graffiti artist puzzles Longford and Mahajan, but Fitch uses his son for inspiration and leads the duo to the perp.
Meanwhile, Longford still doesn't know whether or not he should retire, and Washington asks Fitch to be the godfather of his child.
Agent Harkins discovers the truth about Fitch and Stram in New York, but still doesn't realize that any attempt to take out Stram could jeopardize several innocent people - including Washington, his wife and newborn child.
With the help of Lt. Mason, Longford and Mahajan, Fitch decides to take care of Stram before Harkins and The FBI can get to him.