Note: Payback takes place at the same time as Retribution, book three of the Surgical Strike Unit series. Payback contains spoilers for Retribution. It is therefore suggested that readers read Retribution before reading Payback.A change of conscience leads a cold-hearted spy to risk his life for the woman he loves...Ruthless and arrogant, CIA agent Mark Tonelli has always been driven by two things. The need to avenge his father's death, and the need to protect his country at any cost. But when he joins the top secret black ops groups Kerberos, Mark discovers that there are some lines even he won't cross. He decides to bring down Kerberos from within.Investigative reporter Faith Andrews believes that Kerberos agents have kidnapped her brother and forced him into an experimental scientific program aimed at creating super human soldiers. Running for her life from the men who will kill to keep their program a secret, Faith finds an unexpected ally in Mark. Together they work to stop an upcoming attack to be carried out by Kerberos's enhanced soldiers, including her brother. If the attack is successful, thousands of innocent people will die.Then Mark discovers that his boss is the one who ordered the death of his father and he's faced with a shattering dilemma. Move forward with his revenge? Or protect the woman he loves?