After beloved Ella Farmer dies unexpectedly, all the members of the police district pay a tribute to her, remembering all the hard work and effort she put in her job. They pray together and miss her, knowing she'll be forever in their heart, and that no one can ever replace her as Mannion's right arm.

Without a job and his best friend, Jack takes off to Arizona to play some golf, but not even without his badge he can stop solving crimes. He gets himself involved in a scheme of dirty cops with Mexican dealers and crosses the border to catch the dealer – which he does. Meanwhile, back in D.C., Cavanaugh and Sherry team up to trace Jack and Cavanaugh discovers something that might save Jack's job. Nancy does some investigation on her own and discovers that the guy that died on Brander's hand was injured prior to their encounter, which could clear Brander. Temple and Debreno set up a scheme with Cashmere Brown to bust Lester Richards, who ends up shot to death by Temple.

The third-season opener picks up where the sophomore year ended, with Mannion struggling for his life after being shot on his boat and falling overboard into the Potomac River. As he tries to pull himself ashore, his would-be assassin — the daughter of a Russian mobster — flees the scene and is hit by a car. While the accident brings to light the fact that Mannion is missing, the chief keeps his survival a secret so he can figure out who's behind the shooting. Deputy chief Noland is immediately pressured to solve the case by an aggressive U.S. attorney general, while a new press secretary tries to keep matters from spinning out of control.

When police officer Robert Turner woke up one Thursday morning, he thought it was going to be just a normal day on the force. However, when a car plunged off a bridge into a river, Turner lost his life while rescuing the family inside. Now, Mannion and his team reflect on the life and death of one of their own. (from CBS)

The gangster wars have crossed the limits, leaving a blood trail and innumerous victims. Mannion has Temple working undercovered trying to reach the big boss on the drug dealing schemes. But it's not such an easy road and Temple is forced to try some crack in order to prove he's not a cop. That brings back ghosts from his druggie past, which Temple may no be strong enough to fight again. Meanwhile, Mannion himself interferes with the gangsters, interrogating young 12 year-old Junior about homicides. Later, Parras and Brander are victims of an ambush and are kidnapped by the gangsters. Luckily the police force rescues them before anything happens. Mannion sees no way out but turning to Richard Gray for help. With him, he gets the gang leaders to settle a non-aggression deal. When everything seems to be going back to its places, Temple looks for drug dealers to buy some crack. Ella turns down Clive's proposal to move to Seattle with him, and he decides to stay and marry her. And Mannion

After a man crashes and dies and the police finds thousands of dollars with him, Mannion and his men start an investigation to prevent the dead guy's old girlfriend from being killed. Turns out an old shooter that killed one of Mannion's friend back in New York years ago is the hired killer they're looking for, and the woman they were protecting was behind the plan to kill her current husband and keep the money. It's Jack's second and final chance to catch the guy. Mannion hires a personal wedding dress designer for Ella, who has second thoughts about her marriage. Nancy is diagnosed with Huntington's disease after falling from a fire escape and suffering a concussion while chasing a criminal.

During a struggle, deputy chief Noland shoots a college student he believes is about to rob a convenience store with a gun, but the ensuing investigation doesn't turn up a weapon. Soon, Internal Affairs demands that Noland be suspended, but Mannion refuses to take his badge. Also, the student's wealthy parents threaten to bring charges against Noland.

On Christmas Eve, Temple and Debreno hunt for three dwarfs disguised as elves who robbed a mission truck and were responsible for other thefts in the area, a billy goat who was part of a real-life nativity scene goes missing, Mannion is determined to fulfill ""Santa's"" promise to an 8 year old boy; Parras becomes attached to an abandoned newborn, and Ella has a gift-giving mix-up.

Mannion tells Jenny McLure how his men arrested her brother while she is waiting for her final day. Jenny is dying from AIDS and Mannion makes sure her last days are filled with company and happiness. The cocaine found at Lester's apartment is missing, and Parras becomes of the main targets on the investigation on who switched the coke with sugar. Without the evidence they can't put Lester away, while matches from his pistol are coming from numerous murder scenes. Finally Chief Mannion finds the mole and sends Lester to jail, but unfortunately Jenny doesn't last to see the next morning: she passes away the day before Mannion's event to raise people's awareness on the danger and prevention of AIDS.

Debreno is assigned to protect a country singer, scheduled to sing at the Kennedy Center Honors, who's receiving death threats; Elsewhere, in an effort to lead by example, Mannion hits the streets as a uniformed cop to make quality-of-life arrests on charges such as disorderly conduct, gambling and prostitution. But one of his arrests sparks a chain of events that leads to the reopening of a cold-case murder.

After a black prostitute is found murdered with the inscription ""Respect the Order"" attached to her body, Mannion and his team start a deep investigation that leads to a racial criminal who started serial killing African-Americans who were involved with white people. Meanwhile, Parras sees her father being arrested for requesting the services of a prostitute and has to face her own family problems. Temple helps a friend detox from heroine and Ella investigates a suspicious fire that could promote an officer – but ends up being the reason for his arrest.

After a video where Brander arrests a drug addict is made public and turned into a abuse of power issue, the Mayor demands that Mannion fires Brander, which he refuses to do giving that the man was found innocent. Instantly, a major riot breaks out in the city, with the citizens protesting and attacking the police, demanding that Brander gets fired. Several police cars are bombed and set on fire, and Nancy rescues an officer from an angry riot. He's badly injured, and asks her out when he comes by to pick up his dog. Meanwhile, Temple witnesses his friend Reese die while trying to find the man who shot him. Mannion is trying to save Brander, but when he can no longer live with his guilt he turns in his badge. Unfortunately, the mayor taped Mannion's conversation with Brander over the phone and fired him for obstruction of justice. Late at night, Clive calls him up, saying that Ella died unexpectedly.

Page and Debreno investigate the murder of a reporter, and evidence point them to a wheel-chaired man, who claims the victim was already dead by the time he found her. Mannion goes to NY for his daughter's graduation from police academy and has a hard time saying goodbye to Sherri. Meanwhile, Parras meets a charming man on a cab and thinks he might be ""the one"", and Brander confesses his love for her. Ella goes to Ricky's school to check on why he is having problems with his new teacher, and finds out she looks just like his late mother.

The crime level on District 9 is skyrocketing, and Mannion blames it on Commander Richard Gray, whose performance has fallen under expected. Mannion's actions are recriminated and he is pressured to re-think his decision to fire Gray, but he won't give in. Finally, Gray resigns from his duty, and several cops show their loyalty to him by handing their badges as well. Meanwhile, Officer Parras has to face a performance evaluation when her nightstick breaks on a suspect's face. Later, Ella finds out the sticks are cold sensitive and it wasn't Parras's fault.

Mannion, who is presumed to be dead, pops up in Paris to follow the Government official he believes is behind the attempt on his life. Back in Washington, D.C., Temple is stopped for speeding and an officer finds cocaine in the car, but Temple claims the drugs are evidence he obtained at a crime scene and forgot to turn in.

After a shrinking budget forces Mannion to lay off officers, he takes on a powerful city commissioner he believes is partly responsible for the cutbacks. But the move upsets the mayor, who then looks for an excuse to fire the chief. Also: a congressional witness in a fraud trial claims key case documents were stolen from his hotel room; and Nancy and Brander are injured in an accident while pursuing a suspect.

The mayor is more determined to remove Mannion from office after a man is arrested and dies while in custody, apparently, due to an officer's failure to follow proper procedures. Things get even more intense between the two rivals when the mayor's mentally disturbed son goes missing after being taken to a hospital by two cops.

Mannion has to handle an international crisis after the son of the Colombian ambassador is discovered to be the main dealer of the heaviest type of heroine yet. Threatened not to do anything about it, Mannion studies the international code for diplomatic immunity and plays around until he gets Eduardo kicked out of school and arrested. Meanwhile, Temple helps a heroin addicted woman; Ella has problems with Ricky after he returns from summer camp; Jack Jr. goes to court for his drug problem and Nancy finds Jack a new assistant.

The wife of a heavyweight boxing champion is found murdered in her hotel room, and Temple, the first officer on the scene, comes under suspicion because of a past relationship with the victim, who was habitually abused by her husband. Also: a custodial worker at the police department is discovered to have a false identity.

One of Vanessa Cavanaugh's students commits what she taught to be a perfect murder. No evidence, no witnesses. After the murder confesses to Temple and Debreno his crime, he starts to play with Mannion, who can't seem to charge him since the confession wasn't recorded. Mannion is out to get him for the murder of the father of 3 children and ends up finding a way to link the suspect to the murder scene. Meanwhile, Parras works on a Jane Doe case and finds the victim's estranged mother; and Kendall finds it difficult to end her relationship with a married man.

A doctor who was reporting a crime sees Brander bring in a foreign criminal with a very suspicious disease, which she thinks might be Ebola. Instantly the office is put in quarantine. Without being able to get out, Mannion has to count on Ella, who was at home preparing for her wedding to keep the order while he breaks through Brander's isolation bubble to save his life. Meanwhile, Debreno drives in the snow to find a delirious Temple, who was exposed to the bacteria and might be contaminated with what was later discovered to be a harmless African flu. The next day they all attend Ella's wedding, where Ricky calls her 'mom' for the first time.

Jack Mannion is hired as Washington, D.C.'s new police chief and isinstantly greeted with hostility by the city's top brass, led by chief of patrol Joe Noland, who believes he should have been promoted. Also, this is the Sensitive Beginning of the True, Touching Friendship between Jack Mannion and Ella. This kind of friendship is such a Joy to Watch and we can always use more ""Warming of the Heart"", in these cold facts reality years.

Mannion decides to take every missing case as a homicide case after a rich woman is reported missing, which causes some problems among the African-American community. Debreno is introduced as Temple's new partner, who is still recovering from his fiancée and his ex-partner's death. Ella is back at work, still recovering from breast cancer. Nancy considers going back to the streets as she recovers from Danny's death. Mannion investigates the main suspect on Danny's murder, and finds the suspect's apartment full of pictures of him, Sherry and his children. Sherry leaves and an anonymous call leads Jack to discover the suspect's body tied on his boat's anchor.

Temple and Debreno are working on a carjacking followed by murder case. Parras is suspicious when the victim's fiancé cries but no tears come from her eyes. The case is only solved with the help of a schizophrenic homeless man with multiple identities, who saw the suspect with another man just before the shooting. Temple and Debreno are not getting along, and Mannion has to interfere before Temple (who's much more religious since his fiancee's death, which annoys Debreno) tries to quit. Ella has to handle a strike/budget crisis. Parras is back on the streets and her partner takes it hard when another black man insults him. A snake is left loose around the office.

A construction worker finds the skeleton of a dead boy. He was Noland's last case before promoted - a case that was never solved. Now Noland devotes all his efforts into putting an end to this crime. They finally arrest the boy's mother, who also killed another son of hers. Meanwhile, Mannion tries to change the child abuse scenario in the city. Nick negotiates a possible candidature of Mannion's for the upcoming mayor election. Ella has to fire an old employee but manages to keep him. Parras has trouble dealing with an abusive father that reminds her of her own father, until it is proven that such father never touched his problematic 14 year-old son.