Affinity opens with what appears to be a diary entry written by a spiritualist of some kind in 1871. At a seance, something goes wrong. It's unclear from the text whether it's the spiritualist, an actual ghost, or a mundane accomplice that nearly smothers an impressionable girl and causes a fatal heart attack in a witness. Waters then jumps ahead by about a year and switches perspectives to our primary narrator, Margaret Prior, as she enters Millbank Prison to serve as a Lady Visitor. The idea behind the scheme is that Prior will serve as a good example to the female prisoners and perhaps cut down on the rampant recidivism of the inmates. On her visit, she sees the spiritualist from the opening scene--but doesn't get to speak to the woman until her next visit.
The spiritualist, Selina Dawes, has been accused of fraud and assault. Whenever anyone asks, she blames her "spirit-control," Peter Quick. A few years ago, I read Fingersmith, Waters' other Victorian novel, and as I read Affinity I couldn't help but wonder if there was something similar in play here. No matter how much Margaret wants to see Selina as the genuine article, as a reader you can't really help wondering if Selina is just a gifted cold reader and actress-even if you hadn't been warned by reading something like Fingersmith. Selina also has something else in her favor. Margaret is gay, though this is never explicitly stated in the book other than referencing a few kisses Margaret exchanged with a friend before that friend married Margaret's brother.
Margaret is a perfect victim. She just lost her father. Her mother is a bit of a harpy who drugs her with chloral hydrate to combat her insomnia and depression. Her sister is oblivious to anyone else's problems. Her friend is happily married. All Margaret wants is someone who can understand her desire to be a scholar, and not trapped by everyone else's expectations of her. But the way the Waters spins the story out, there are events and phenomena that challenge anyone who doesn't debunk for a living to rationally explain away. In Selina's diary, she never references any plans for deception or evinces any scorn for the people who flock to her seances. She appears to manifest a spirit that can interact with her audience. She knows things that she shouldn't now. And, perhaps the best evidence in her favor: Margaret receives gifts from Selina in her own home. It's hard to explain how flowers and a velvet collar appear in Margaret's room while Selina is constantly watched in prison.
Affinity is set against the mid-Victorian craze for spiritualism. Few people were as immediately skeptical as a modern person would be. The book is set inside a run down, cold, leaky prison in the early 1870s. Prisoner rehabilitation was as much about the prisoner's immortal soul as it was about getting them to reform. The mentally ill were as likely to be tossed into jail as they were into an asylum. Given our protagonist's predisposition when she starts visiting, it's little wonder that Margaret falls under Selina's spell.
This is a cleverly written book. I don't want to give away the ending. So I'll say that until the very end of the book, I was equally convinced that Selina was a con or that she was actually a medium. I'm not going to say anything more except to say that you'll have to read the book to figure out which is true.