In 1891 a mine collapsed into itself. What was the dark substance found 666 feet underground? Blending modern horror, historical fact, and Western lore, Scott Snyder and Dan Panosian have created a uniquely terrifying thriller with Canary. While the marshal’s tragic past continues to reveal itself, he and Ed-Ed meet more of Canary's key figures, with one in particular that might forever change the course of Holt's investigation.