The Highway by C. J. Box, a Mysterious Review.

Review: When Danielle and Gracie Sullivan, two sisters traveling to Montana via a Yellowstone National Park bypass, stop communicating with Danielle's boyfriend, he begins to worry and asks his dad, Cody Hoyt, to look for them. But Cody has just been suspended from the police force for planting evidence and has no authority to do so. Still, he calls upon his former partner, Cassie Dewell, to assist him in The Highway, a stand-alone thriller by C. J. Box that features in supporting roles several characters from his previous stand-alone, Back of Beyond.

It was Cassie's evidence that helped bring Cody down. As a diversity hire in the department, she was promoted to Investigator over men with more seniority and who were undoubtedly more qualified to do the job. Still, with a young son and mother to support, she needs the higher pay that accompanies the position and agreed to spy on her partner. After he is suspended, she visits him to try to explain when Cody's son tracks him down with the news that his girlfriend and her sister have gone silent. Cassie agrees to help, though she has no authority as the missing girls are out of her jurisdiction. Separately, they take on a search, but when Cody goes missing, too, Cassie is alone to find the answers to what happened to her partner and the girls … and are the two incidents connected?

The first third of The Highway is really quite compelling, a psychological thriller with edge-of-your-seat tension. But then it all kind of stalls. It's almost as if the author couldn't decide where to take the story at this point. The suspense element completely dissolves as the plotline turns into a police procedural-style mystery, not a whodunit or howdunit but one in which it isn't clear how — or if — Cassie is going to capture the girls' kidnapper.

None of the principal characters here are relatable or even likeable. The good cops are bad, the bad cops are worse, the bad guys abhorrent. It's even hard to make a connection with the other ancillary characters or feel sorry for the victims, who, with one exception, are annoying in and of themselves and tend to grate on the reader.

There are a couple of half-hearted attempts to add misdirection by referencing an anti-government cult based nearby but these are never fully investigated and fall flat as plot points. As does Cassie's sense that the girls may be in the hands of a serial killer, which happens to be true, but she's too naive or inexperienced to follow through on her instincts. And yet, incongruously, she goes in confident — and alone — to save the day in the end. Alas, The Highway ends on an ambiguous note suggesting a third book to feature one or more of these characters may be forthcoming.