Oath of Loyalty (Mitch Rapp book 21), by Vince Flynn, Kyle Mills (Kindle) 99p @ Amazon

As a new generation of assassins comes together, the world turns against Mitch Rapp

With President Anthony Cook convinced Mitch Rapp is a threat, Irene Kennedy is forced to negotiate a truce: Rapp must stay out of the country while Cook is in control of the White House. In return, they won’t make moves against him. But the new CIA director has a different plan.

Going after his partner, Claudia Gould, puts Rapp right where Cook wants him. As her cover is blown and enemies from her past resurface, the race to neutralize them is on. But a new kind of killer, a shadowy group known only as Legion, is on her tail. They can’t be called off and they won’t back down until their target is dead, no matter how long it takes. No one has ever been able to identify them. In fact, no one is even completely sure they exist . . .