Firefly

In this impressive if flawed thriller from British author Porter (The Bell Ringers), Luc Samson, an ex-MI6 agent hired by his former employer, tries to locate 13-year-old Naji Touma, who has fled his native Syria for Germany to reunite with his family. Authorities suspect that the boy, recruited against his will into ISIS for his technological skills, managed to encrypt a wealth of secret ISIS data on his cellphone, including hundreds of videos showing ISIS leader Al-munajil (aka the Machete) decapitating innocent Syrians. That last fact hasn’t escaped the notice of Al-munajil, who has set out with a handful of henchmen to get to Naji and his phone before Samson does. Porter excels at describing the life of trekking migrants and the atmosphere in the camps of Greece. The plot, however, sags from inaction as Naji makes his way across Southern Europe and his pursuers try to stay close. A lively ending helps, but many readers may have grown frustrated by then. Still, fans of Porter’s previous books will find much to admire. Agent: Emma Parry, Janklow & Nesbit. (Oct.)