Tanya Huff brings her series of novels about feisty Toronto private investigator Vicki Nelson to a conclusion in Blood Debt.

Henry Fitzroy -- romance novel writer, bastard son of Henry VIII and 450-year-old vampire -- has left Toronto for Vancouver in order to make room for another vampire. Normally, he'd stand his ground against an intruder on his turf, but in this case, the new vampire is none other than Vicki Nelson.

It has been two years since the grisly living nightmare in a Queens University life sciences laboratory which resulted in Henry "changing" Vicki as the only means of saving her life. He is happily ensconced in Vancouver with Tony, a former street kid. Although normally he would not maintain contact with Vicki after the year of teaching her how to hunt for her food, through Vicki's persistence, he has maintained cordial communications with her.

For her part, Vicki is now living with Mike Celucci, who in turn has become accustomed to being the lover and occasional snack for a vampire who brims with vigor. Vicki has continued to be a private investigator, although her activity has since been constrained to evening hours, and one night, she gets a call from the last person she ever expected to have as a client: Henry Fitzroy.

Lately, upon waking at sunset, Henry has been confronted by a silent ghost. Henry soon learns that he may ask one question. If the answer is "yes," then the ghost leaves for the rest of the night. If the answer is "no," then the despairing wail of the ghost causes someone, usually an innocent, to die. Henry knows that hiring Vicki is his only chance of figuring out what the ghost wants. His phone call leads to an unexpected development -- Vicki wants to go out to Vancouver with Celucci and take on the ghost in person.

Henry knows that the city is too small to handle two vampires, but Vicki soon proves him wrong. After a nearly deadly start, they strike an uneasy truce and, with Celucci's help, begin to unravel the mystery, involving organs, organ donors (willing or not), doctors, philanthropists and television talk show hosts. Although Henry stubbornly tries to resist this clear violation of vampire law, he finds that perhaps the rules aren't so cut and dried.

For the most part, the pace is breakneck, although the continued tension between Henry and Vicki begins to pall a bit as the reader wishes they would just realize that they can get along perfectly well. Although the story has a dark swath in it, there is plenty of humor which balances the book. Huff incorporates telling details: for example, vampire Vicki tends to fall into her morning sleep right in the middle of a thought.

Although it's sad to think there will be no more Vicki Nelson books, Huff makes a wise decision in bringing the series to a close, and she has chosen just the right place for it. This whole series stands up to the test of rereading. If you're a Huff/Nelson fan, then you owe it to yourself to pick up Blood Debt.