Molly Kimball has found a lot to love. And though she's not quite ready to use the "L" word when it comes to her boyfriend Kieran, she's definitely fallen for his intimidating family's library. His family is paying her handsomely for an updated catalog, when Molly discovers the original manuscript of 'A Fatal Folio'. Though purportedly written by an ancestor of Kieran's, no one has ever been sure of the author behind the pseudonym. Kieran's cousin, Oliver, offers to help look into Selwyn's identity. A professor in Gothic literature, he's eager to publish a paper on the mystery - especially because a student, Thad, is threatening to file a complaint against him. On Bonfire Night, Molly, Kieran, and her friends set out to enjoy the fun. All goes as planned - at least until a stray firework starts a panic, and the group stumbles upon a prone body, their face covered by a mask. It's Thad.