This article aims to convince readers of the value of intersecting the scholarship of interdisciplinarity with the field of argumentation studies. The interdisciplinarity literature has not much engaged with the vehicle that carries interdisciplinary learning, languages, and locutions: the argument. On the argumentation studies side, despite the diverse interests of these scholars, not many have studied how reasoning proceeds in interdisciplinary inquiries. To aid bridge-building from both sides, I use the example of interdisciplinary abductive reasoning to show how the two fields can benefit from each other. The article proceeds as thin, comparative case studies thickened by theory. By analyzing two extended cases of inquiry cast in Douglas Walton's argumentation terms, I argue Walton's model is necessary but not sufficient for understanding and dealing with the unique challenges of interdisciplinary abduction. I propose, instead, we add the PEPR model (Pattern Recognition, Explanation Imagination, Pattern Matching, and Reporting) to help us focus on the data to be explained while we lean on Walton's model to understand the people doing the explaining. I conclude argumentation studies and interdisciplinary theory can be mutually enlightening.