Quick recap
On the Philadelphia subway, Reacher distrusts a passenger, Anna Merrick, and watches her take her own life. Two detectives question him, and armed men demand a USB drive he doesn't have. With Anna's brother Jacob and detective Tamara Green, he learns the drive proves a crime from years back in Indonesia, tied to Congressman Sampson. A pair of assassins, the Hoths, want a chemical weapon, and the fight ends with Reacher wounded and the drive in a journalist's hands.
