A young prostitute's body is retrieved from Vancouver Harbour, and Sunny notes striking similarities to a string of previous deaths. A chance comment to Da Vinci leads him to re-open several cases, causing a further rift with his ex-wife Patricia, who did the original autopsies, and with his boss James Flynn, who ruled the deaths as accidental.

Da Vinci reopens several cases, causing a further rift with his ex-wife.

Da Vinci is convinced a serial murderer has been on the loose for years.

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.

Following a rash of fatal drug overdoses, Da Vinci learns that one of the dead addicts had an infant, who is missing. Manny, a police informer leads Leary, with new partner Angela Kosmo, to the woman's drug dealers. They arrest Todd and Sioux, and through them Larry discovers that the killer heroin came from a French-Canadian supplier who, along with his partner, was murdered, gang-execution style, just days previously.