Biologist and graphic novelist Jay Hosler has long been introducing young readers to biological subjects through entertaining narratives combining strongly fictional elements with nonfictional ones. Extensive application of fiction to nonfictional subject matter is uncommon, even in graphic novels, but Hosler's "The Sandwalk Adventures" (2003) makes an illuminating case study in the pedagogical benefits of entwining fact and fiction. The book, an introduction to the basic concepts of evolutionary theory, revolves around conversations between Darwin and a pair of young follicle mites residing in his eyebrow. Two competing tales of origins, theistic and scientific, emerge in the telling. In the first section of the paper, I show how Hosler deploys their rivalry to cast doubt on the factuality of received "facts" and to cultivate openness to verifiable ones. In the second and third sections, I analyze the functions of "Sandwalk's" literary form, a simulation of conversational storytelling: it helps Hosler illustrate selection pressures and processes, and engage readers in a scientific mode of thought.