Susan Squires has written several books based on her concept of "The Companion," a parasitic/symbiotic blood disorder that confers strength, immortality, healing and ability to compel peoples' minds, all set in the early 1800s. Like her other books, One with the Night follows a similar theme: a vampire male who has suffered much torture under a strong vampire woman has to face his fears when falling in love.

These books are all well-written, with interesting settings and varied characters. In this story, Callan Kilkenny, an Irish/Scottish vampire, is searching for the cure for his vampirism and understands that a scientist believes he has almost found it. When Kilkenny arrives at the scientist's house in Scotland, he identifies the reason for the research - the scientist's daughter, Jane Blundell, is a new vampire (it turns out she was accidentally infected by some of the stored vampire blood that her father had). Kilkenny fights and kills a vampire who has come to kill the scientist as the possibility of a cure is a threat to some of them. Kilkenny realizes that he will have to guard the scientist and Jane to ensure they are safe as they work for the cure. He also volunteers to be the guinea pig for each new batch of the formula.

Almost immediately, Kilkenny and Jane find themselves attracted to each other. He knows it's part of The Companion's influence on them, but she knows nothing about her condition and doesn't find Kilkenny very forthcoming about it. She questions him but seldom receives helpful answers. When three more vampires arrive to help with the search for the cure, Jane realizes that there is a lot more to being a vampire when she sees Elyta, an old vampire, using her compulsion on Kilkenny. Can Jane and Kilkenny find the cure? Can they escape the evil influence of Elyta? Can Kilkenny come to terms with his past and the things he has done?

A problem that many people have with Susan Squires' books (and I am one of them) is the detailed descriptions of the tortures her heroes undergo. In this book, it is less in the backstory (flashbacks, a device she uses in each book) but is detailed in events that take place in the timeline of the novel. The scenes of male rape are very distasteful, and the reader can get the impression that Squires enjoys writing these parts a little too much, especially as such scenes are in all her Companion books. These are erotic stories, but the main emphasis of this writing seems to be on the tortures and rapes rather than the relationship between hero and heroine. She depicts the mental anguish of the hero throughout his experiences well, and Jane also grows to learn of the effect her father's opinions of women have had on her. However, this character development is subsidiary to the main plot of the attempt to find the cure and of Kilkenny's torture.

There's a guest appearance in this story by Nessie (the Loch Ness Monster) which is amusing, but overall the dark tone of the story and the torture and rape descriptions don't make this easy reading.