Reaper by Valerie Ullmer

A wolf-shifter and his powerful human.

Reaper had expected it to be an easy assignment. Break into a biotech facility with minimum security and rescue a group of immortals who were subject to deadly experiments and eliminate those who might try to fight back. But the moment he walked into the glass prison and spotted a human woman being held with the immortals, his mission changed.

She became his mission.

Before Reaper had a chance to explain that he was there to help her, she blinded him and the rest of his team and slipped away. Although she had escaped him, a protectiveness that he’d never felt washed over him, and he became determined to find her.
Ara has always depended on herself, but there was something about the shifter that made her want to trust him. She recognized him as someone who was capable of protecting her as well as understanding her secrets without turning her away, but before she could allow herself to trust him, she ran.

But with no resources and running out of ideas about how to protect herself, will she be able to lower her defenses and allow the shifter to help her?