A stray greyhound turns up in an Alabama animal hospital and dies a day later-the culprit: enough fentanyl in the dog's stomach to kill three grown men. Arlo Riggins, the owner of a top-tier brokerage firm and state-of-the-art dog sanctuary, enlists the help of his friend to investigate whether the incident was a one-off or part of something bigger. Enter Declan Wyler and his canine partner Blackjack, a highly trained Belgian Malinois. Currently idling his days away as a part-time gambler and security guard, Wyler agrees to look into the matter. As a former Marine dog handler during the wars in Afghanistan and Iraq, he is skilled in tracking people who don't want to be found.

When Wyler and Blackjack arrive in Alabama, their investigation leads them into the deep woods. After a brawl with some local thugs, they're put on the trail of a man desperate to pay off an inherited debt by any means necessary.