Chicago's Major Crime Unit, that can operate slightly outside the law and is led by hardboiled lieutenant Mike Torrello, stops a violent team of armed robbers one night, but their leader escapes. Torrello suspects the head to be Ray Luca, a young ruthless and ambitious mobster on the rise. Luca soon convinces Johnny O'Donnel, one of the people Mike cares for, to join his crew, but this ends up having deadly consequences. Mike must also deals with idealistic public defender David Abrams, who highly disapproves of Mike and his team's sometimes borderline vigilante methods. However, Luca sees this as Abrams' weakness and uses it to get on Abrams good side, by pretending to be clean. However, Luca still has to follow orders of his higher-ups, even though he's trying to remove their influence over him.

Chicago's Major Crime Unit, that can operate slightly outside the law and is led by hardboiled lieutenant Mike Torrello, stops a violent team of armed robbers one night, but their leader escapes. Torrello suspects the head to be Ray Luca, a young ruthless and ambitious mobster on the rise. Luca soon convinces Johnny O'Donnel, one of the people Mike cares for, to join his crew, but this ends up having deadly consequences. Mike must also deals with idealistic public defender David Abrams, who highly disapproves of Mike and his team's sometimes borderline vigilante methods. However, Luca sees this as Abrams' weakness and uses it to get on Abrams good side, by pretending to be clean. However, Luca still has to follow orders of his higher-ups, even though he's trying to remove their influence over him.

A psycho killer becomes the MCU's top priority case. Luca uses the manpower shift to his advantage by pulling off major heists.

A psycho killer becomes the MCU's top priority case. Luca uses the manpower shift to his advantage by pulling off major heists.

Lt. Torello and the MCU search for the person responsible for the murder committed during a home invasion. Feeling the heat from the MCU's home invasion investigation Phil Bartoli orders Ray Luca to take care of the problem personally.

Lt. Torello and the MCU search for the person responsible for the murder committed during a home invasion. Feeling the heat from the MCU's home invasion investigation Phil Bartoli orders Ray Luca to take care of the problem personally.

Luca plans to take over the gambling business and sends one of his men, Holman, to St. Louis. Torello plans to take Holman down, but the local sheriff, who wants publicity gets in MCU's way.

Luca plans to take over the gambling business and sends one of his men, Holman, to St. Louis. Torello plans to take Holman down, but the local sheriff, who wants publicity gets in MCU's way.

Luca's takeover of the gambling business comes to a halt and Torello hits his other operations even harder. However, Torello suffers a major loss in his private life.

Luca's takeover of the gambling business comes to a halt and Torello hits his other operations even harder. However, Torello suffers a major loss in his private life.

A pretty female reporter helps public defender Abrams defend a man accused of assaulting a slumlord and he falls for her. Torello, on the other hand, must help his wife get through the tough times.

A pretty female reporter helps public defender Abrams defend a man accused of assaulting a slumlord and he falls for her. Torello, on the other hand, must help his wife get through the tough times.

Abrams pursues a relationship with Suzanne Terry, the reporter who helped him, but he's condemned by most because she's African-American. Torello and his wife have a rocky vacation. FBI finally locates Holman.

Abrams pursues a relationship with Suzanne Terry, the reporter who helped him, but he's condemned by most because she's African-American. Torello and his wife have a rocky vacation. FBI finally locates Holman.

Shocked Torello discovers that his old friend is working with the mob. A federal investigator, who's about to indict Luca, suspects Torello is dirty. Luca tries to stop the indictment.

Shocked Torello discovers that his old friend is working with the mob. A federal investigator, who's about to indict Luca, suspects Torello is dirty. Luca tries to stop the indictment.

Angered by the death of his friend, Torello decides to ignore the FBI and goes after Holman himself. Luca goes into fencing business. Abram's girlfriend Suzanne is attacked while investigating street drug dealers for her new piece.

Angered by the death of his friend, Torello decides to ignore the FBI and goes after Holman himself. Luca goes into fencing business. Abram's girlfriend Suzanne is attacked while investigating street drug dealers for her new piece.

As his marriage disintegrates, Torrello starts a relationship with lovely Inger Thorson, assistant of one of the jewelers Luca's crew murdered. MCU stops a new crew of robbers. Luca makes a deadly move against independent fences.

As his marriage disintegrates, Torrello starts a relationship with lovely Inger Thorson, assistant of one of the jewelers Luca's crew murdered. MCU stops a new crew of robbers. Luca makes a deadly move against independent fences.

A clip show recapping the story thus far. All major plot events and character development moments are covered and some previously cut scenes shown for the first time.

A clip show recapping the story thus far. All major plot events and character development moments are covered and some previously cut scenes shown for the first time.

MCU faces an armed robbery that turns into a hostage situation. Holman is caught, but overly ambitious Federal prosecutor Harry Breitel asks him to testify against Luca's crew as well as Torello's team.

MCU faces an armed robbery that turns into a hostage situation. Holman is caught, but overly ambitious Federal prosecutor Harry Breitel asks him to testify against Luca's crew as well as Torello's team.

Luca gets indicted and Torello is next, so his boss orders him to take a vacation. Luca tries to find someone to take out Holman in jail, before he testifies. He also asks naive Abrams for legal advice without disclosing the details.

Luca gets indicted and Torello is next, so his boss orders him to take a vacation. Luca tries to find someone to take out Holman in jail, before he testifies. He also asks naive Abrams for legal advice without disclosing the details.

Mike is indicted and used by Luca to destroy Holman's testimony. However, Abrams, feeling guilty for being foolish, helps Mike. Mike breaks up with Inger to protect her from scandal. The Dancer, an ex fence and Abrams' dad, shows up.

Mike is indicted and used by Luca to destroy Holman's testimony. However, Abrams, feeling guilty for being foolish, helps Mike. Mike breaks up with Inger to protect her from scandal. The Dancer, an ex fence and Abrams' dad, shows up.

Torello testifies in court to prove his innocence, but emotions in the courtroom heat up quickly. Local boss Dominic Tranchita breaks the mob's golden rule and starts dealing drugs. He even clashes with the mob council over the issue.

Torello testifies in court to prove his innocence, but emotions in the courtroom heat up quickly. Local boss Dominic Tranchita breaks the mob's golden rule and starts dealing drugs. He even clashes with the mob council over the issue.

The mob makes its move to take over Las Vegas casinos. Abrams and Torello gather a team and set up an undercover operation in the strip club that Luca's men frequently visit.

The mob makes its move to take over Las Vegas casinos. Abrams and Torello gather a team and set up an undercover operation in the strip club that Luca's men frequently visit.

A general strike hits Las Vegas casinos. Luca decides to get the strike leaders on his side one way or the other. Meanwhile, Torello's team must track down a gang that bombing and setting fires to both casinos and the picket lines.

A general strike hits Las Vegas casinos. Luca decides to get the strike leaders on his side one way or the other. Meanwhile, Torello's team must track down a gang that bombing and setting fires to both casinos and the picket lines.

Torrello falls for Lisa, ex-wife of Abrams's assistant, Steve Altman, but Altman is psychotic and possessive and tries to get Lisa and her daughter Tracy back by any means necessary. Also, FBI undercover agent infiltrates Luca's casino.

Torrello falls for Lisa, ex-wife of Abrams's assistant, Steve Altman, but Altman is psychotic and possessive and tries to get Lisa and her daughter Tracy back by any means necessary. Also, FBI undercover agent infiltrates Luca's casino.

Luca forces the owner of Palladium, the biggest Las Vegas casino still not controlled by the mob, to give in. Meanwhile, Jack Claymore, the undercover FBI agent who's infiltrated Luca's casino meats Torello and becomes compromised.

Luca forces the owner of Palladium, the biggest Las Vegas casino still not controlled by the mob, to give in. Meanwhile, Jack Claymore, the undercover FBI agent who's infiltrated Luca's casino meats Torello and becomes compromised.

The case against Luca is dropped, so Luca gives in to his inner demons to celebrate the fact that he now owns Vegas and the cops can't touch him. Torello uses these Luca's personal flaws and violent tendencies against him.

The case against Luca is dropped, so Luca gives in to his inner demons to celebrate the fact that he now owns Vegas and the cops can't touch him. Torello uses these Luca's personal flaws and violent tendencies against him.

Luca's closest friend and associate Paulie Taglia testifies against him, after out of control Luca rapes his girlfriend. L.A. crime boss Nat Martino tries to push Luca out of Vegas. Luca learns Martino's big secret and fights back.