Da Vinci investigates a death among the mutinous crew of a Chinese freighter. Meanwhile, Kosmo and Leary delve deeper into the police beating of a young drug dealer.

The Mayor & the new Police Chief stand in the way of Da Vinci and his on-going investigations of a hit-and-run and a police beating. Meanwhile, Kosmo is investigated by Internal Affairs and Shannon & Rose work the case of a mummified baby found in a dumpster.

Da Vinci begins to suspect that a widespread conspiracy is protecting the Mayor in the hit-and-run investigation. Meanwhile, a murdered drug runner turns out to be a childhood friend of Leary's and Kosmo's relationship with Sue attracts the attention of Internal Affairs.

While Da Vinci remains at odds with the Mayor and Police Chief he attracts attention from Ottawa. Meanwhile, Leary and Kosmo discover that a murdered drug runner was under police surveillance and Shannon's reaction to a personal loss puts his job in jeopardy.

Da Vinci discovers he's the target of a private investigation. Meanwhile, Brian further implicates Sue in the murder of one of his informants.

Da Vinci must get the support of the mayor and police for his red light district proposal. Meanwhile, Sue is secretly interrogated by Internal Affairs and Angela desperately tries to get her.

Da Vinci is up to his eyeballs when the media learns of the mayor's involvement in the hit-and-run, at the same time the wife of a dead longshoreman insists her husband was killed by his co-workers. Meanwhile, Leary uncovers a possible Russian connection in the murder of his childhood friend.

Da Vinci investigates a body in the sewer. Meanwhile, Brian accompanies Rose on a homicide case, and Kosmo is troubled by a witness from the past, at the same time that Shannon, while moonlighting as a hotel security guard, discovers some dirt.

Da Vinci manipulates both sides in the upcoming race to his own advantage. Meanwhile, Brian and Rose investigate the suspicious suicide of a key witness.

A decision from the Mayor and a fatality at the safe injection site bring Da Vinci's political future into focus. Meanwhile, despite being demoted to robbery, Kosmo is happy to learn the Crown is investigating Brian's policework, and Leary catches a break when a potential witness to Will's murder comes forward.

Da Vinci gathers his political allies hoping to emerge as a front-runner for mayor. Meanwhile, Leary races to arrest Will's murderer before the DEA can slip him across the border, and a body in a burned-out car and an arson fire at Kosmo's house may be ominously connected.