Forged in Steele / Maya Banks.

Enhanced descriptions from Syndetics:

The next heart pounding novel in the KGI series from Maya Banks, the New York Times bestselling author of Rush , Fever ,and Burn, the Breathless trilogy.

The Kelly Group International (KGI)- A super-elite, top secret, family-run business.
Qualifications- High intelligence, rock-hard body, military background.
Mission- Hostage/kidnap victim recovery. Intelligence gathering. Handling jobs the U.S. government can't...

Steele, a KGI team leader, is an enigma not even his teammates understand. His emotions are tightly locked down and nothing can break that icy exterior. Nothing except Maren Scofield, a doctor on a mission, a woman who has gotten under Steele's skin and threatens to crack that unflappable cool he's legendary for.

Steele is determined not to allow Maren past his carefully guarded defenses. But when she's in danger, there's no way he'll allow anyone else to protect her.

Maren's hiding something. He's sure of it. But he isn't prepared for the shocking discovery her secrets reveal. Or how they will forever alter the course of his destiny. He has a decision to make. Hold tight and shut her out. Or take a chance on something more powerful than he's ever faced- Love.