In the very first chapter of “It’s Not Her,” Mary Kubica describes in detail a violent double murder. One of the main characters and narrators, Courtney, witnesses the brutal slaying of her best friend Emily and Emily’s husband, Courtney’s brother. The other main character is Courtney’s niece, Reese. Cleverly, while both narratives are in first person, Courtney narrates what is happening in the now, while Reese’s narrative explains the events of the preceding week.

Because Courtney’s brother Nathan married her best friend Emily, the families are close. Nathan and Emily have three children, the eldest, rebellious teen Reese, moody fourteen-year-old Wyatt, and ten-year-old Mae. Courtney and her husband Elliot have one daughter, Cass, who is the same age as Mae. The girls are close friends as well as cousins. The two families have gone to a resort in northern Wisconsin for a week of togetherness, and while the resort is not as nice as they thought it would be, they are together.

The only ones who really seem to be enjoying the togetherness are the two preteen girls. While they giggle, swim in the pool, and steal Elliot’s iPad, tensions arise between siblings Wyatt and Reese, and marital problems are exacerbated between Nathan and Emily. Reese meets and becomes infatuated with the creepy guy who works at the resort cleaning the pool. And while he’s really repugnant to us, Reese is only seventeen and on the outs with her friends. He’s handsome and seems to like her, so she meets him at night for thrills. It assuages the loneliness she feels in her social life.

Courtney’s account is about the events after the murder, what the police are doing to find the killer, and how the family is dealing with the new reality. Through her eyes, we see the strange actions of her husband, Elliot, and Wyatt, her nephew. Both have exhibited some unsettling behaviors, and she wonders if either of them might be the murderer.

Through Reese’s account, we learn about Daniel, the very sketchy guy she has a crush on. In Kubica’s capable hands, we are very aware of the angst of teenage years when young girls feel every insecurity that social media has thrust upon them. Reese is grateful for the attention that Daniel is showing her, even as he keeps that attention hidden from the adults, insisting she meet him in the middle of the night. It’s very obvious that Kubica wants us to consider Daniel as a likely suspect in the double murder.

This novel is definitely a slow burn. At the start, Kubica sets up the atmosphere at the rustic, run-down resort. The endpapers in the finished book are striking, with a nighttime view of a forest that makes us envision the forest surrounding the cabins, even blocking most of the lake view. It’s also in the forest where Reese meets Daniel for midnight trysts. Kubica’s descriptions are effectively detailed; we can almost smell the mildew and dust in the shabby cabins, the mold in the single bathroom they all share, and hear the creaking boards of the deck outside the cabin.

But as the two narratives continue, we are drawn into their lives, and as we understand all the foibles of the characters, the tensions between them, and the anger that some hide, we are really invested in figuring out who is the murderer. Late last night, with the last 50 pages still to read, I lay awake going over all the characters to try to figure out who it was. I was not successful.

In addition to a fabulous twisty plot and several characters who might be guilty, Kubica creates the perfect amount of tension. The alternating narratives, past and present, are extremely effective and add to the intensity of the plot. We realize that both narrators are slightly unreliable as they each have their own internal doubts and insecurities, and that adds to the drama. Kubica also presents a twist after the shocking resolution, a twist that I am sure no one would have guessed. Masterful writing makes this an intense read.

This review was first posted on Bookreporter.com.