When Dawn falls ill, it's up to best friends Buffy, Xander, and Willow to join forces and find a supernatural cure in a world sorely lacking magic. The trio must fight their way into the Deeper Well, the former home of Illyria and other ancient gods known as the Old Ones, where they hope to jump-start magic back into existence. But when they discover the volatile Severin and Simone, a Slayer gone rogue, looking to gain access to the Well, Buffy's mission must shift from saving her sister to saving the world.