Extremities - C. A Devine

Disgraced NYPD Lieutenant Mac Ryan is desperate to flee his new unwelcome celebrity after his undercover investigation implodes and his partner is killed in a shootout with a notorious Afghan drug baron. Escape is offered aboard a Mediterranean yacht where an enigmatic English writer, Max, appears equally intent on escaping her past.
But when Max is abducted right in front of him, Mac is dragged into a world of deception, conspiracy and spooks where he must finally face his personal daemons.MI5 agent Lizzie 'Lucky' McKenzie has just gone AWOL. She is on a personal crusade of revenge. Someone must pay for a war crime that has gone unpunished and she is prepared to act as judge, jury and executioner. But her handlers and her last mark are both on her tail. And her target has turned out not to be the cruel soulless individual she imagined. Is he really guilty of the appalling crime? Her pursuers are upon her, but her resolve is wavering.
Should she exact justice while she has the chance?