The Wolf Assassin’s Mate by Lorelei M. Hart

Being a protector isn’t supposed to be easy or glamorous. I never expected it to be. We have one job: to keep shifter-kind safe from those who would do us harm. Sometimes that means doing the ugly and violent things others want to pretend don’t happen. I’m fine with all of that, knowing I’m making the world a better place.
When I get my new mission, I plan to go in, annihilate the threat, and get out. Easy peasy.
Only it’s anything but when I find myself face-to-face with my true mate being held against his will and very, very pregnant. My oath as a protector no longer matters. I have two jobs to do—save my mate and shut down the breeding ring holding him captive—the one run by “the good guys” I work for.