Fate's Promise. Altered Karma Series, #3

A devoted scientist and the test subject she can't stop fighting for must trust each other with their lives - in a facility designed to make sure neither of them makes it out. Ten years ago, a super volcano in Thunder Valley reshaped the world. Phoenix Corps stepped in to rebuild it - and Faith Moira believed them. Recruited straight out of school to study the Tempest Program - soldiers engineered to withstand extreme temperatures - she's never questioned her work.
Until she's assigned to Seven-Nine-Four-Five, the one subject the Tempest Program couldn't predict. Cole has survived horrors she can barely comprehend, and he has no reason to trust her. She's one of them, as far as he's concerned - another face behind a clipboard while Phoenix Corps tears him apart. But Faith is starting to see the cracks in everything she believed, and what she finds buried in classified files will force a choice: her career, her safety, or him.
She holds his fate in her hands - and somewhere between what she uncovered and stolen glances, she stopped pretending she didn't care what happened to him. His survival is the only promise she intends to keep. She's spent years trusting Phoenix Corps with everything. Now the only person worth trusting is the one she was never supposed to see as human.