Checkmate by Greg Rucka Book 2

"After the explosive events of INFINITE CRISIS and THE OMAC PROJECT, the U.N. formed Checkmate to bring down heroes and villains that get out of line. Using their unique abilities to deputize human and metahuman forces, this agency pulls out all the stops in pursuit of its goal to maintain balance between worlds. Having finally secured the political backing they needed to survive, Checkmate's operations begin in earnest, as an agent tries to infiltrate the terrorist group Kobra! But someone within Checkmate seems to be working against them, and a compromised agent is forced to make a deadly, life-changing choice!"--