Katie Alender’s The Companion got me out of a recent reading slump. It’s a fast-paced nail biter of a book, one that begins as a creepy mystery and transforms into a suspense novel that had me turning the pages as quickly as I could.

When Margot is plucked from the group home she’s been living at since her family died in a car accident and sent to be the ward of a wealthy family that lives in a huge mansion in the countryside, she doesn’t know how to feel about it. Her family’s death and her status as an orphan are still new and fresh, and she doesn’t know what kinds of strings are attached to the proposal.

Turns out there is a big string: she is to serve as the companion to the Suttons’ severely mentally ill teenage daughter, Agnes, who became mute and almost unresponsive several months ago – a stark change from her prior carefree, dynamic personality. The implication for Margot is clear: if she refuses to spend most of her time with Agnes, which includes sleeping in the connecting room, she’ll be sent back to the group home. While Margot is not thrilled with the arrangement, she does feel sympathy for Agnes, and she begins to develop a bond with her.

She also begins to more fully explore the huge house that she now calls home. Big, sprawling, and old, it has a lot of history and a lot of secrets, secrets which Margot starts to unravel in her nighttime wanderings when she can’t sleep. And soon the family that seemed generous and kind, if a little eccentric, starts to show its darkness.

Alender does a great job of initially making the family seem very sympathetic and reasonable, even when the things they’re asking of Margot are pretty odd (and even when the reader should know better!). Mrs. Sutton and Margot form a genuine friendship, and their relationship is, at first, even therapeutic for Margot in managing her grief: they bond over gardening, and the lack of a cell phone signal on most of the property gives Margot the temporary space she needs from the rest of the world.

But there are warning signs. The Suttons refuse to give Margot the wifi password, making excuse after excuse that they don’t remember it or can’t find it. There’s a locked garden and evidence of another girl who once lived in the house but is never mentioned by the Suttons. And Agnes seems to be trying to tell Margot something important.

Careful or experienced readers will know the big secret pretty early on, but the story is still an engaging read without that particular plot point being a mystery. Margot herself takes a bit too long to catch on to what’s really happening (and how it connects to what happened in the past), but once she does, Alender switches handily from “what the heck is going on” mode to “will Margot survive this?” mode. It’s effectively written at all parts, generating huge amounts of suspense and leaving readers almost breathless with concern and hope for Margot, whom we’ve come to care for deeply. Alender is a talented writer of suspense and character; this is a standout example of both.

Finished copy provided by the publisher.