Proof, though central to mathematical practice, is rarely explored through the lens of embodiment because of the centrality of abstraction and generalization. We use the case of a high school geometry student to investigate two research questions: (1) How do embodied processes facilitate mathematical learning? (2) How can generalized mathematical truths be manifest through embodied processes that are grounded in particular movements? To engage the body, researchers developed a motion-capture video game, "The Hidden Village," designed to elicit physical movement via in-game directed actions. In-game interactions complement logic and verbal forms of reasoning by promoting simulated actions, which are shown to recur during the student's proof and justification. Embodied theories of learning offer insights into how learners recruit body-based resources to foster meaning-making and generalization. Embodiment also offers new insights into re-characterizing mathematics curricula in terms of movement, and the promise of new forms of embodied learning technologies. [This paper was published in: "ICLS 2020 Proceedings," ISLS, 2020, pp. 175-182.]