Reacher: Bad Luck And Trouble by Lee Child

From a helicopter high above the California desert, a man is sent free-falling into the night. On the streets of Portland, Jack Reacher is pulled out of his wandering life and plunged into the heart of a conspiracy that is killing old friends . . . and the people he once trusted with his life.

Reacher is the ultimate loner—no phone, no ties, no address. But a woman from his old military unit has found him using a signal only the eight members of their elite team would know. Then she tells him a terrifying story about the brutal death of a man they both served with. Soon Reacher is reuniting with the survivors of his team, scrambling to unravel the sudden disappearance of two other comrades. But Reacher won’t give up—because in a world of bad luck and trouble, when someone targets Jack Reacher and his team, they’d better be ready for what comes right back at them.