Number 13 in Lee Child's "Jack Reacher" series, and a very good one. As with most entries, you have to buy into the premise: Jack isn't looking for trouble, just traveling around the great USA, but keeps falling into the middle of incidents that start out seemingly small, but eventually are revealed to be the phenomena of an underlying evil plot.
In this case, Reacher is on a Manhattan subway around 2AM when he notices that one of his fellow riders is exhibiting most of the telltale signs of a suicide bomber: a heavy coat in summer (no doubt concealing a large amount of explosive); a fixed stare; lips continually mouthing something, perhaps a Muslim prayer; one hand concealed in a bag, perhaps a detonation switch.
Reacher confronts the passenger—that's the kind of guy he is—and immediately discovers that things are not what they seem; it's a different kind of desperate situation, and he's plunged into his usual milieu: in big trouble with the authorities, but able to find some allies; investigators that show him bogus identification; other investigators that don't think they need to show any identification at all; a missing witness; ties to a Senate candidate with a mysterious military past; an equally mysterious beautiful woman with an unsavory companion. And so on.
Even though the reader knows it's just one entry in the Jack Reacher series, and hence Reacher will make it out OK at the end, it's a tribute to Child's prowess as a writer that he's able to put him in deadly peril and make me wonder: is this the end for Reacher?