Sharon Bolton’s latest, The Pact, capitalizes on a theme we have seen before, in everything from I Know What You Did Last Summer, the teen thriller by Lois Duncan, to Donna Tartt’s The Secret History. That doesn’t make it any less impactful, however—especially in the hands of a master of psychological fiction.

Five entitled young people and their one friend on a scholarship are spending their summer vacation (while awaiting their final A level marks that will determine their future at University) hanging out together, indulging themselves in drink, drugs, and indolence. The various effects of this provoke a dare game in which they all pile into a car in the wee hours of the morning and drive the wrong way between two ramps on a motorway (freeway). Each of them in turn has done it, with no real consequences but with some near misses, but when the final person’s nervous driving leads to tragedy, all the six can dwell on in that moment is how it will impact their futures should their wrongdoing come to light.

Amidst turmoil, hysteria, and guilt, accusations are made and fingers are pointed as they all seek a plan to protect themselves. Finally Megan, the scholarship girl, offers to take the fall—to claim she was driving by herself and that she alone was responsible. In return, she asks that when she is done serving her term in prison, each of the others will owe her a substantial favor. Caught up in the giddy relief that only one of them will suffer, the others all agree to her terms without questioning her motivation. They craft their story carefully, not realizing that outside circumstances will substantially affect the case against Megan; she ends up being sentenced to 20 years, instead of the three to five they expected.

Twenty years later, the others—Talitha, Felix, Xav, Amber, and Daniel—have all made significant achievements in their careers, as well as most of them accumulating spouses, children, and wealth. Meanwhile, Megan has served her full sentence and has suffered injuries while imprisoned that have left her physically and perhaps mentally damaged. Now comes the reckoning, the part where Megan gets to name her terms and the others must comply. As they each contemplate the guilt over having shunned and ignored her during her incarceration, the secret shame they feel at wishing she’d not been released, and the fear of the price she will exact, the tension builds.

Although the story is involving and well told—in both the present and the past—it is the character studies that make this book so compelling. Sharon Bolton is so good at creating unlikeable characters and then causing the reader to hope they get what they deserve while simultaneously pondering how he or she would have reacted in their place! As each of the five considers Megan’s admittedly outrageous requests and flails around crafting a response, you realize it’s just a matter of time until someone snaps. But that realization is far from the result of knowing who it will be, which is the trick that keeps you reading to the end.

Bolton has written another gem of a thriller that first defines and then shreds the concepts of friendship and loyalty in the face of unbearable tension. While it’s not my favorite of her books (because of the plot, less original than most), it’s definitely worth a fingernail-gnawing evening or three!