Yacht Club Games announces a September 17th release date for Plague of Shadows, a free content update for Shovel Knight, their side-scrolling platformer (thanks Kotaku). This trailer offers a look at what this will provide, and here's word:

Grab your potions and don your mask, it’s time to play as Plague Knight! Shovel Knight: Plague of Shadows is a free update is primed to appear on all existing platforms and regions on September 17th, 2015!! Whether you’re on your favorite system or trying the game in a new way, we hope you enjoy this free update featuring an all new alchemical adventure and Challenge Mode!