The squad gets involved in the world of street racing.

When Ali is on her way back from a routine prisoner transfer, Winslow accidentally crashes the car (somewhere off highway five between Clearwater and Little Fort), leaving Ali and himself relying on the prisoner they're transporting, Paul King, who is accused of the brutal murders of two men. Ali and the prisoner both beg Mitch to uncuff Paul so that he can help them (Ali has a spike through her arm and Mitch has suffered heavy internal injuries), but Mitch absolutely refuses. When Mitch finally dies from his injuries, Ali begins to talk to the prisoner, who maintains his innocence in the murders and swears that he's only out to save the environment.

Years ago, Pierre Martin was convincted of murdering Randall Bettinger, but suddenly Bettinger turns up alive and well, making Len, who had busted the case, look very bad. Within 48 hours though, Bettinger is found dead for real, and Casey brings in both Nicco and Len to work the case, and each uses their snitches to help prove who murdered Bettinger. Mickey gets pulled in when the murder of 6-yr-old Jeannie Yan is reopened after nearly ten years, because the girl was the first dead child she ever saw. She asks Ali to investigate, and when Ali begs off, Mickey begins doing some detective work of her own.

After a taxi driver reports a passenger who seriously gave him the creeps with his misogynistic views on women, Ali decides to look into it, and the trail leads her to Ian Summerhill, a dentist who had dated the first missing woman and had been dating the woman found a couple of days after the cabbie came in. Sam tries to investigate Summerhill's dark side and heads back to her old work place, where girls entertain men for money. Ali's relationship with Paul is threatened when Ian shares some stories of Paul's mis-spent youth with her, and she wonders how accurate they are.

The squad discovers what happened with Billy Wells and Michelle Ripley.

Frank and Nicco are stripped of their badges over the drug probe.

After comic book Steve Baker owner is shot at, Ali takes another look into the disappearance of a young woman named Thora who everybody believed Steve had murdered. At Ali's request, Ray begins 'protecting' Steve from Thora's father David and former boyfriend Mark while trying to uncover some dirt on him. Harper is pre-occupied with his wife having kicked him out of their home, and when she and her parents cut him off from seeing Eva and Kassia, Harper finds his world falling apart.

On August 2, 1982, two young boys disappeared. When the body of one was found later, they used the child's backpack to help identify him as Benji Harding, the son of a firefighter. Sixteen years later, a former co-worker of Harding's sees a computer screensaver featuring pictures of a child he swears is harding. Simms calls Lloyd Mastrowski in to work on the case, since he worked the original, and it isn't long before they realise the body belongs to Christopher Kowalchuk. During the course of the investigation, suspicion turns to Lyle and Grace Burgoyne, a family whose son died sixteen years ago in a fire when Harding was unable to save him. The case has political implications because the Kowalchuks spear-headed numerous missing childrens' campaigns after their son went missing, only to finally be told there was never any hope.

Ali receives a letter from Denny Lavoie, the hit man who had died earlier, in which he tells her about the death of Nancy Seniuk a bag lady found dead in Stanley Park on August 17, 1980, but there is still a lot of mystery surrounding it. Using some of the modern tools, they age the photo they find of Nancy back to her twenties to begin the investigation. Ross takes Ali out to dinner and starts to tell her about the Seniuk case. Ali gives him a hard time about it and he drops it, but she suggests they go back to the office where he tells her about a drug operation called Deception in which four drug informants were killed. He believes there's a leak in the department. Add to the intrigue is Chief Malcolm warning Ali away from involvement in the case and Ross' investigation, suggesting his obsession with the operation is a wild goose chase. Ali becomes uncertain who she can trust.

Courts rule evidence in a murder case inadmissible prior to a retrial.

A cold case turns warm when a mysterious man collapses near a hospital.

When Ali's testimony results in the release of a killer (Dean Bulmer), Coscorella takes it too seriously and makes catching Bulmer his sole goal, much to the displeasure of homicide detective Len Harper. Nicco is furious with Ali and believes she should have lied to keep Bulmer in jail, and tries desperately to keep the father of one of the victims from taking justice into his own hands. Cold squad is in danger of being closed down, and the officers absorbed into the homicide division.

Marcey Bennett was only fourteen when she was found raped and murdered in April of 1986. The gardener, Matthew Dalton, was arrested for the crime and later confessed. While cleaning out some of the junk in Sam's office, Max finds a videotape showing the investigation and when he and Ali realise how horribly the scene was contaminated, Ali decides to take another look into the case. With the focus on a former cop turned judge, Lance Giffen, Tony accuses Ali of being out to get all cops, still not over what happened with Vince Schneider. Ross decides to let Ali take an unofficial look, but warns her about Logozzo's drinking.

Thirteen-year-old Kevin Lane disappeared on June 6, 1979. Years later, his parents discovered that his former baseball coach Harry Walters was really pederast Martin Woodridge, his mother became convinced that Woodridge murdered her son and hid the body. Woodridge insists that he is all about consenting actions between adults and young adults, insisting that he has never forced anyone to do anything they didn't want to. After the Lanes offer a $100,000 reward for information, Woodridge comes forward and points the finger at himself. Although Ali would love to lock him up and throw away the key, she just can't do it.

Harper struggles to build a case against a murder suspect, after an investigation that lasted 18 month long.

Harper searches desperately for his missing daughter, praying that he will find her before it is too late. Sam has the perfect suspect, an well-known surgeon, but the only witness against him is very unstable.

A skull and a computer-generated image lead the squad to the parents of a 14-year-old rape victim.

Ali and Tony find a corpse hidden in a building that turns out to be Edmund Kritch, an anti-radical that disappeared over twenty-five years ago. While Tony investigates former members of a radical group known as Code Red, Cortez is convinced that the dead man's boss is behind everything, and Ali suspects the dead man's former girlfriend. Nick and Ali finally take their flirtation to the bedroom, where Ali is shocked to learn that Cortez was there first.

A murder investigation leads to dissension in the squad.

After getting himself arrested while on a camp-out in the United States, Harper goes undercover to smoke out marijuana traffickers and in his discussions with the squad soon realises that minor dealers have been dying mysteriously. His objectivity is seriously challenged when he finds himself falling for Lila, the innocent sister of one of the main suspects.

A 12 year old case where a murdered woman's death matched the M.O. of a now-convicted killer seems to be yet another victim. Until investigation shows the killer couldn't have done it. He was already in prison. McCormick and Logozzo try to find who was the original killer and who was the copycat. This two-part episode introduces Inspector Simon Ross.

When Gavin Yeung, a wealthy Chinese teenager, commits suicide in jail cell, it brings up haunting memories for Logozzo of a similar suicide when he was a young cop; a young Philippino teen named Guillermo Santayana, also from an extremely wealthy family. The situation and people involved are enough for McCormick to reopen the case of Willy Santayana and to investigate not only Newlock and Stollard, but Logozzo as well. She and Logozzo, who is looking into the Gavin Yeung charge despite being warned off, need to be careful though, because Ross doesn't want them anywhere near the case. When Logozzo goes calling on Neil Stollard, an old comrade who now works at the jail, and causes repercussions, Ross warns them to stay away from the active case. Eddie and Cortez take the Maurice Patterson case, Cortez because she refuses to have anything to do with the Santayana / Yeung case.

Mickey and Ali investigate a twelve-year old murder that was believed solved thanks to a tip from a junkie named Simon. Coscarella investigates when two dogs trained by the same man attack people on command. Christine cannot resist the lure of her past, and steals cocaine from the lock-up.

Police corruption may have played a role in drug-gang activities.

Frank investigates the death of a forgotten war hero. Ali applies to become a Big Sister after questioning her value as a cop