In the real world, many reversal phenomena occur, such as cases where a statement once regardedas false is later recognized as true. Upside-Down Logic is a framework designed to formalize such reversal phe-nomena as a logical system. It inverts the truth and falsity of propositions through contextual transformations,thereby capturing ambiguity and reversals within reasoning processes.A Plithogenic Set models elements by means of attribute-based membership and contradiction functions,extending the classical frameworks of fuzzy, intuitionistic, and neutrosophic sets. However, the role and ef-fectiveness of Upside-Down Logic within Plithogenic Fuzzy Sets, Plithogenic Intuitionistic Fuzzy Sets, andPlithogenic Neutrosophic Sets have not yet been sufficiently explored.To address this gap, this paper investigates Upside-Down Logic in these three plithogenic settings. In partic-ular, we analyze how contradiction values guide the application of Upside-Down Logic and provide illustrativeexamples of its use. Furthermore, we consider application cases of Upside-Down Logic in Plithogenic FuzzyGraphs. Through these studies, we aim to demonstrate that Upside-Down Logic offers a formal means to modelreversal phenomena arising from contradictions under uncertainty. We also define a method of resolving con-tradictions, referred to as De-Plithogenication. Through this process, for instance, a Plithogenic Fuzzy Set canbe transformed into a structure resembling a classical Fuzzy Set