Her Undercover Defender (The Specialists- Heroes Next Door Book 4)

She's the perfect pawn 

Covert CIA specialist David Martin has his orders. Keep a terrorist cell from using Terri Barnhart as leverage to get their hands on a nearly perfected biotech weapon. Falling for her could compromise his mission and turn the dedicated nurse into a moving target. 

With her brother off the radar for three months, Terri fears the worst. Having the sexy Southerner to lean on helps—except the hospital's new staff member isn't what he seems. To survive, she'll have to trust David with her life—trusting him with her heart is something else entirely.