Dark Shadows 30: Barnabas, Quentin and the Mad Magician by Marilyn Ross

 Dark Shadows 30
Barnabas, Quentin and the Mad Magician
by Marilyn Ross
1971 Paperback Library

World famous magician Cabrini comes to Colinwood, placing a character under his hypnotic spell.  A series of throat slashing murders casts suspicion on Quentin, while Barnabas helps solve the mystery,

Is the murderer the sinister magician? Is it one of the two main characters? Or is it...no, it's the magician.  There is no mystery here.  This jives with the mood of what I remember from the series: we have werewolf boy not being a werewolf, vampire boy not being a vampire, and people discussing the discussions they've had about things that happened off page.

Paperback from AbeBooks

Audiobook available, check your library

Dark Shadows by Marilyn Ross

 Dark Shadows
by Marilyn Ross
1966 Paperback Library

You grew up in an orphanage, knowing nothing about your family.  You get a job offer as a governess in a spooky house owned by a family who have been secretly financing your care.  A word of advice - if you are going to make out with any of the boys, I suggest you don't look at the hidden portrait in the locked basement.

Not a novelization, but a parallel set of stories to the gothic soap opera. Like the soap opera, the book series never answers the question of Victoria's parentage after being hijacked by time travelling vampires (though a Big Finish audio play does).  This installment has a self-contained mystery, but we never find out if she's in love with her probable half-brother and/or nephew.

I've never read a proper gothic romance, but this hits every square of the bingo card I've picked up from Scooby-Doo: stranger at the window, hidden portraits, secret passages, a locked room nobody's allowed in, suicide, madness, etc.

Available in Kindle and paperback from Amazon.

And check your library for an audiobook version