Indexical storytelling is increasingly popular in games, where fragmented clues drive narrative discovery and player interpretation. However, the non-linear nature of these clues poses challenges for systematic organization and story reconstruction. To address this, ClueCart was developed—a creativity support tool designed to help creators categorize narrative clues and facilitate complex story interpretation through a hierarchical taxonomy. In a controlled study (N=40) comparing ClueCart to Miro, ClueCart significantly improved the efficiency of organizing and retrieving clues, better supporting creative workflows and offering insights for future player-centric narrative analysis tools.