Metal Heart by Michelle Frost

When stray human Matthew wanders into Black Dog shifter pack territory, he’s injured and vulnerable. The last thing Matthew expects is for the pack’s alpha to be the home he’s always been looking for.
Bram can’t believe his nose when the trespasser his enforcers drop at his feet turns out to be something entirely different. Nursing Matthew back to health becomes Bram’s priority, but the pack isn’t thrilled to have a human in their midst.
When the pack gives them an ultimatum—either Matthew joins the pack in truth or leaves—the only question is, if he decides not to stay, will Bram be able to let him go?