Payback: The SSU Book 4

A change of conscience leads a cold-hearted spy to risk his life for the woman he never thought he would want...

Ruthless and arrogant, CIA agent Mark Tonelli has always been driven by two things. The need to avenge his father's death, and the desire to protect his country at any cost. But when he joins the black ops group Kerberos, Mark discovers that there are some lines even he won't cross.

Kerberos is changing honorable men into mindless killing machines. Mark's long-dead conscience roars...