Colin by Regan Black

He’s ex-Army. She’s a witness in danger. Together they must fight the ghosts of the past to survive the killer on her trail.
Summer Curley is on the run after her witness-protection detail is gunned down. With no one to trust, she can only hope that hiding will buy her time enough to make a plan.
Colin Hazard’s Army career ended after weeks as a prisoner of war. Now he finds purpose as a bodyguard and when he’s assigned to locate and protect an important witness, he dives into action.
But keeping Summer safe is only the first problem. Colin soon learns the case and the woman are far more complex than he expected. Between her secrets and the ghosts haunting his past, staying alive could mean sacrificing his heart.
When hope is lost, truth is blurred, and your life is on the line, it’s time to call in the Guardian Agency.