Koyomi Araragi returns home to find Karen suffering from an intense fever—a symptom of the bee's sting. He discovers that Tsubasa Hanekawa has been secretly cooperating with his sisters to track down the source of a curse spreading among local middle schoolers.
The Karen Bee arc serves as a sequel to the Nadeko Snake segment from Bakemonogatari . While Karen is a self-proclaimed "hero of justice," the arc explores the difference between "real" and "fake" justice. Kaiki represents the "fake" supernatural, yet his impact on Karen is dangerously real, forcing Koyomi to intervene to save his sister. 4 : Karen Bee, Part 4
The episode picks up after Karen has been afflicted by a supernatural "Wreathe-Fire Bee" oddity. Koyomi Araragi returns home to find Karen suffering