When television news reporter Hope Martin (Lynda Boyd) breaks a story about mercy killing, Detectives Leary and Shannon start digging around for more details, and Da Vinci calls a Coroner's Inquest to force Martin to reveal her source. The issue of euthanasia is divisive and as the investigation proceeds Da Vinci finds himself at odds with the police and his superiors about the reality and the ethics of what happened. His elderly father's recent debilitating stroke further complicates his response.

Danny Leary is back in town, but the reunion with his older brother Mick is far from idyllic. It looks like he is hooked on drugs and, unbeknownst to Mick, hanging around with two hoods that turn up dead.

Da Vinci, Leary, and Sunny are in Seattle attending an international Homicide Conference. A presentation by San Francisco-based FBI Special Agent Charlotte Turner turns up similar cases across the Pacific Northwest, and appears to include the death Da Vinci is currently working to solve. Turner comes to Vancouver and Da Vinci finds himself coordinating an investigation that has international implications. As more abductions/murders fit the pattern it seems that a couple, Dean and his wife Mona, are responsible. Joanna, a young woman who was abducted but managed to escape, leads Shannon and Leary back to the farmhouse where she was held and they arrest Dean. Mona, however, has managed to sneak across the border into the States and Da Vinci offers Danny a deal if he can find out where she is. Meanwhile Da Vinci finds himself struggling with the ethics of paying Dean for information about other victims.

Working with Shannon and Leary, Da Vinci investigates an apparent suicide in the woods of an ex-convict released on day parole. Patricia starts her new job as a professor at the university. Sunny finds some artifacts of interest in historic Chinatown. Detective Kosmo tries a new approach to an old unsolved case.

Da Vinci investigates the death of an Aboriginal Peoples needle-exchange worker. Meanwhile, Rose and Leo take on a case after a man receives a severed finger through the mail.

Da Vinci investigates a hit-and-run involving the mayor's car. Meanwhile, Leary & Kosmo looks into the suspicious beating death of a drug dealer.

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.