The Devil's Sanctuary by Marie Hermanson
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Psychologists say that there are psychopaths everywhere. Next door? You boss? Maybe you married one?
Daniel and Max are twins. They were separated when they were young by their parents' divorce. They then grew up very differently from each other.
After a long absence, Max arranges for Daniel to leave his humdrum daily grind and visit him at a swank resort/rehab facility. When he arrives Max spins a story about his need to leave the fcility for a short while to arrange finances. Daniel agrees.
Things unwind for Daniel after that. The hospital is, in fact, more of a prison set up to research psychopaths. The residential population of the resort are composed of psychopathic personalities. Daniel desperately attempts to disclose the truth, but try as he might no one believes him because he is believed to be Max and Max is a habitual liar.
I found this to be a captivating page-turner. I enjoyed this book. It's not a great book. The first half of the book takes a bit too long to get into the story. Then, when the plot picks up speed, the pay-offs are just a bit too quick in coming, and, then, they come in by way of monologues. Honestly, I enjoyed having my suspicions confirmed, but it was just a bit too easy.
I came to this book by way of the “Sanctuary” (2020) mini-series on Hulu. The series is gender-swapped; Daniel and Max are now Siri and Helena. This change actually improves the story. A colony of psychopaths is incredibly dangerous, even more so for women, I'd imagine. The sense of tension is heightened in the TV series I think I will be scoring the show better than the book.