Boston narcotics detective Eddy Harkness is on the case again, and this time the soul of the city is at stake.
When a late-summer hurricane slams into Boston, Detective Eddy Harkness and his Narco-Intel crew are thrown into the eye of a very different kind of storm. Dark Horse -- an especially pure and deadly brand of heroin -- has infiltrated the gritty Lower South End. Harkness soon finds that the drug is also at the center of an audacious land grab by the city's corrupt new mayor and his shadowy power brokers. Meanwhile, Lower South End residents displaced by the storm use an obscure bylaw to move into Eddy's hometown, and soon enough tensions are running high along Nagog's tree-lined streets. Fast-paced and atmospheric, Dark Horse moves from dive bars to Harvard dorm rooms to the city's elite social clubs, as Harkness puts everything at risk -- his department, his nascent family, and his life -- to try to derail the seemingly unstoppable conspiracy before it's too late.