The Last Renter: An Archer Island Thriller

by Caleb Mason

What do you know about that person in your short-term rental unit?

In The Last An Archer Island Thriller, a dangerous mental patient escapes to Archer Island seeking revenge against her abusive stepfather and holds her elderly rental hosts captive in their remote farmhouse.

Millicent Kilvert has led a tragic life of mental illness, culminating in her being sent to an insane asylum to live out her life. She manages to escape and after killing her mother heads for Archer Island in late-November as a big coastal storm rolls into Maine. She rents the attached bungalow in an old farmhouse owned by an elderly couple, Hilda and Evan Olson. Evan leaves his wife alone with the renter as he takes the ferry to the mainland to help their pregnant daughter move into a new home. Hilda and Evan are excited to become first-time grandparents and are unaware of their renter's past.

That first night as the storm rages, Hilda hears strange noises coming from the attached rental unit. When she creeps downstairs to investigate, what she finds will change her life forever. Will her husband Evan be able to make it back in the storm to save her? Can Hilda convince her hallucinating guest to let her seek help?

The Last Renter is a psychological thriller exploring serious dissociative mental illness and paints a sympathetic portrait of a tragically damaged young woman.

Genres: Mystery

320 pages, Paperback

Published April 7, 2026

Reviews

[Michele · Rating 3 out of 5]

I won this book in a Goodreads giveaway.

There was a lot to unpack in this book. The story premise was good. Millicent's character had a lot going on. She was very complex and disturbed but with touches of clarity. There were a few side stories with other characters that seemed a bit much at times. While it was nice to have some back story to the other characters, I feel there was a enough going on with Millicent at the rental, that the book didn't need the other stuff.

[Angela Costa · Rating 4 out of 5]

I really enjoyed this book. This couple went through it. The author was able to put you right there in the moment. The characters were humans and flawed but not irredeemably so. Well most of them. Enjoy this thriller.. I certainly did

[Mandy · Rating 2 out of 5]

The Last Renter by Caleb Mason is an atmospheric psychological thriller that combines the claustrophobia of a home-invasion narrative with a deeper, more unsettling exploration of trauma and fractured identity. Set on the remote Archer Island off the coast of Maine, the novel begins with a deceptively simple premise: an elderly couple rents out a small bungalow attached to their farmhouse. Their tenant, Millicent Kilvert, turns out to be an escaped psychiatric patient with a violent past, driven by abuse and psychological instability. When a storm cuts the island off from the mainland, the story tightens into a nerve-wracking siege. Millicent is not presented just as a simple villain but as a deeply damaged individual shaped by years of abuse, with dissociative tendencies that manifest in a violent alter ego. Stylistically, Mason writes clearly and accessibly with no literary flourishes. His use of shifting perspectives and flashbacks adds depth, gradually revealing the forces that have shaped Millicent’s character. It is definitely more than just a thriller, but a dark, unsettling study of how violence can emerge from suffering, and how thin the line can be between victim and perpetrator. Up to a point I found it a gripping narrative, but I felt that there was simply too much violence, especially in the early pages, so much so that it became numbing rather than disturbing. It felt like just one attack after another, which stretched credibility. An enjoyable read, but perhaps a bit of restraint would have been welcome.

[Frank · Rating 2 out of 5]

I thought the setting and the premise of the book were interesting, and I generally liked the character of Millicent, especially as we gain a better understanding of how her mind works and why.

What I didn't really understand was the violent episodes (on the mainland) that were tangent to the main plot - these felt like a distraction from the overall story rather than a supplement to it; and I felt they undermined the concern we (the readers) are supposed to be feeling at that point in the story.

There were also multiple instances where unnecessary political commentary seemed to have been just dropped in without adding to the story or creating any kind of character depth.

[Christine · Rating 2 out of 5]

I disliked this thriller! Full of unnecessary violence (I don't mean the main setting...), I wondered why? It took away the earnestness of the main plot, and made the novel (for me!) not believable. I thought the storyline might be interesting as it deals with mental illness, but there was no depth in it !! The author uses the term of sociopath, when I believe, psychopath would have been the right word to use. To me , a rather disappointing thriller.
I received a digital copy of this novel from NetGalley and I have voluntarily written an honest review.

[Jackthedad · Rating 1 out of 5]

Thanks to NetGalley and Publerati for an advance reader copy. If you want a synopsis, click on the book.

I found the overall story okay but there were so many deaths in and around such a small island, I felt the plot became unrealistic. I tired of the God talk, especially at the end. I was particularly annoyed at the inclusion of an unnecessary character who was transitioning. This is merely pandering to stupid wokery for less than 1% of the population and I knocked a star off because of it. I finished it but this book is not for me.

[Ellen · Rating 4 out of 5]

I really enjoyed this book. I love the setting - the island, the storm, the details of place are beautifully drawn. I love that most of the characters are older, and their lives are portrayed as important and not stereotyped. I appreciate that through all the bad things that happen, the bad choices the characters make, I believed those choices. Millicent is well-developed - traumatized and destroyed, but with flashes of self-awareness, understanding, and regret. This is not an easy book to read at points, but it is well worth the journey.