The series followed the adventures of Nick Knight, a Toronto cop working the graveyard shift with his partner Donald Schanke. Unbeknownst to most of his colleagues, Nick is actually Nicholas, an 800-year-old vampire (his human name was a pun based on his status as a literal knight in medieval France). Remorseful over centuries spent as a vampiric cold-hearted killer, Nicholas works as a cop and often ends up using his special abilities to bring criminals to justice. Nicholas explains his need to work on the night shift by claiming to have a skin disorder, photodermatitis, which requires him to stay out of sunlight. Refusing to feed from humans, he survives by drinking bottled animal blood, something that most vampires find repulsive. The only one who knows his true nature is his friend Natalie Lambert, a city medical examiner who doesn't like for Nicholas to use his special powers as she believes it increases his need for blood. Nick's ultimate dream is to find a way to become human once again, but his quest for redemption is complicated by the arrival of fellow vampires Lucien LaCroix and Janette DuCharme. LaCroix, who was born in the Roman Empire, and Janette, whom originally made Nick a vampire, were his companions for many centuries. Janette now runs a night club, while LaCroix works as a late-night talk radio host. While Janette is scornful yet tolerant of Nicholas's new lifestyle, LaCroix actively attempts to seduce his protégé back to a more violent life. During the series, Nick had two partners. At the beginning of the third season, his first partner, Detective Schanke, is murdered, and he is partnered with Tracy Vetter, a rookie detective who gets the assignment due to her father's high-ranking position in the police force. Tracy is never aware of Nick's true nature but finds herself increasingly attracted to Javier Vachon, a vampire who had been a conquistador in life. Although Nick continues to protect the "innocent" civilians, he finally gets tired of the life he lives. Nick is faced with the choice to either move on or attempt to recapture his humanity through a method that puts Natalie's life in the balance. At that point LaCroix appears and indicates the time to leave is near and he must either bring Natalie over or leave her to die. Nicholas decides that neither option is acceptable and hands LaCroix a wooden stake. We do not see what LaCroix does, but we hear him say "Damn you, Nicholas" in stress and frustration, and the scene pans out to the building where Nick lives. The ending is left to the viewers' interpretation but the implication is that Nick dies with LaCroix's help, hoping to join Natalie in an afterlife.