When Kyle Dickman set out on a spring road trip with his wife and infant son, he was fueled by a carefree sense of adventure that had defined his life. Then he got bit by a rattlesnake in a remote part of Yosemite National Park. The harrowing event changed his entire outlook on the world. Now he’s on a quest to understand the toxins that nearly killed him—and trying to come to terms with a world where everything slithers.