Research indicates that investigating phenomena, rather than reproducing facts, should be a core experience in the education of prospective mathematics teachers. Corresponding with its centrality to quality teacher education, there are multiple existing methodologies for analyzing the effects of investigation tasks on teachers' mathematical development. In this study, we demonstrate the potential of a novel method of data collection, the scripting journey, as an avenue for describing mathematical activity that takes place during an investigation. Participants, comprised of prospective and practicing teachers, explored the concept of a star polygon and wrote a scripting journey based on their deliberations, ideas, and conclusions. We analyzed their submissions using the construct of advancing mathematical activity, which allowed us to explore the examples of symbolizing, defining, algorithmatizing, and theoremizing that appeared within participants' scripting journeys.