⭐️ ⭐️ ⭐️ ⭐️ ⭐️/5
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Head Cases took me completely by surprise—and I loved every page of it.
This is an intelligent, character-driven police procedural that stands out in the crowded world of FBI thrillers. At its core is Agent Gardner Camden, a brilliant puzzle-solver with sharp instincts, emotional blind spots, and a quietly devastating personal history. He’s not your typical G-Man—and that’s exactly what makes him such a compelling lead.
Gardner heads up the Patterns and Recognition (PAR) Unit, a fringe FBI task force in Jacksonville made up of brilliant misfits who were all sent there for making mistakes or stepping out of line. The team is unconventional, awkward, and endlessly compelling. They don’t play by Bureau rules, but they solve the cases no one else can.
When DNA from a new murder victim links back to a long-dead serial killer, the team is thrust into an active case—rare for them. As more bodies drop, it becomes clear that the killer is leaving behind riddles specifically designed for Gardner. And this time, the case isn’t just professional—it’s personal. The killer knows things they shouldn’t, and the PAR team must stay one step ahead before the trail turns toward them and their families.
What sets Head Cases apart is its deeply flawed, emotionally rich cast. Each member of the PAR Unit is working through some form of damage—professional, personal, or both—and yet their quirks and failings are also what make them exceptional at their jobs.
Gardner is socially awkward, possibly neurodivergent, and entirely devoted to solving puzzles and doing what’s right—even when it’s cost him everything: his marriage, custody of his daughter Camila, and his career trajectory. Still, he wouldn’t change a thing. Cassie, his new partner, transferred to Jacksonville under murky circumstances and shares Gardner’s analytical mind and eye for detail. Their dynamic is layered and full of potential. And hopefully some smoochin’ in the later books. Shooter (yes, that’s what they call her) is the wildcard—an eccentric, badass weapons expert who might just steal the show. Frank, the team’s leader, brings quiet authority and calm—but he also seems to be keeping secrets. Richie, the new recruit, is sharp and capable… but the fact that his personnel file is sealed adds an intriguing mystery to the mix.
The plot moves at a gripping pace, with just enough twists to keep you guessing. The riddles and killer’s pattern are cleverly constructed without feeling gimmicky, and the final reveal genuinely surprised me. It’s amazing to be able to watch Gardner’s brain unravel the clues.
But what I loved most was how authentically human this story feels. Gardner’s neurodivergence isn’t romanticized or exaggerated, it’s simply part of him, and it shapes the way he processes the world, leads the team, and tries (imperfectly) to connect with his daughter. The emotional undercurrent between him and Camila is quiet, but it’s the heart of the book.
This is the kind of series opener that makes you want to binge-read sequels that haven’t even been written yet. If you’re a fan of Criminal Minds, Profiler, or simply love watching a team of outsiders crack impossible cases, this book is for you.
Sign me up for every future PAR Unit release. I’m hooked.
Thank you so much to the author, John McMahon, Netgalley and St. Martin’s Press | Minotaur Books for the ARC copy of this book.
The Head Cases is out now! You can grab your copy here.
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