Windward - Mirror Series, #2

Grant's new-found happiness with his submissive Matty is shaken when he learns that Jaeger Koning, fugitive assassin and Matty's ex-Dominant, has returned to America. Over Grant's objections, Matty accepts the FBI's request to assist in the capture, but Jaeger is always one step ahead of them, and Grant discovers too late that Jaeger's true goal is to reclaim Matty.