In this thriller, a British soldier–turned-operative finds his world upended when his nephew is killed by a CIA agent’s wife, who flees to escape the consequences.

This series opener begins with two crosscutting events: British secret agent Toby Miller takes out a bomb maker in an unnamed country, and Madyson Lutz, distracted and driving on the wrong side of the road, runs over a teen cyclist. The accident happens near the British base where Madyson’s CIA agent husband has been working. The fates of these characters soon intertwine since the cyclist, who dies from his injuries, is Toby’s nephew. Madyson’s husband hustles his wife back to the United States, angry that she has messed up his career but claiming diplomatic immunity for the incident. Toby is told the news by his bosses, ordered to take a break at his former British army barracks, and watched regarding his mental state and potential for vigilantism (“Miller’s a bloody potent weapon, Her Majesty’s Armed Forces saw to that, and now we’ve given him more training, more responsibility, more deadly skills. He’s capable of a lot”). Lucy Bell, the policewoman who arrived at the accident scene, is part of the team sent to interview Madyson, although officials imply that extradition is unlikely. Once this proves to be the case, Toby, whose sister and brother-in-law are suffering greatly from grief, travels to the U.S. to kill Madyson. But the situation turns out to be not at all what Toby expects. Green’s thriller has an intriguing inciting incident, prompting its core characters to create and rally around a “4DC,” or For Diplomatic Change, movement. The book’s midsection gets bogged down a bit with conversations among various officials who are ultimately minor characters. But overall, the story is a well-paced page-turner driving readers to its dramatic meeting between Toby and Madyson. Toby is also an appealing series protagonist, with his tough-guy persona leavened by both humorous and emotional interactions with family and others.

An engaging tale highlighting the tensions of diplomatic immunity and introducing a surprisingly endearing hero.