## 3 Methods
### Decisions and Prototype
#### 3.2.2 Player Mode of Co-Relay  
The Co-relay system offers 2-4 player modes, each providing a distinct cooperative and interactive experience tailored to players of varying group sizes. Initially, participants select a character card and customize its appearance to heighten immersion and personalization. Subsequently, users receive a semi-open script outlining the relevant environment, such as the story's setting. Within the virtual reality (VR) environment, users explore to uncover story fragment cards, including those containing passwords. By collecting a specified number of these cards (n > 5), users unlock subsequent key storylines resembling quests that offer clarity and deeper insight into the narrative. Throughout the VR interaction, users engage with story fragment cards to facilitate communication and collaboration. These interactive cards facilitate information exchange, resource sharing, and suggestions, thereby enhancing the frequency and depth of strategic discussions and team decisions. Participants collaborate to gather clue story fragment cards containing essential details for solving the mystery, including motives of suspects, specifics of the crime scene, and eyewitness accounts. Through the integration of their respective clues, participants engage in reasoning, discussion, and a step-by-step revelation of the truth. The Graphical Abstract (GA) illustrates the structure of the Collaborative Relay System. This process challenges the user's logical thinking and cooperative skills, heightens the complexity of integrating narrative fragments, and offers the enjoyment of puzzle-solving and the satisfaction of constructing a coherent storyline using story cards. As clues emerge, this interactive experience builds towards a climax culminating in the final card. Endings are determined by the user's narrative reasoning, reflecting their storyline decisions and problem-solving approaches. Each ending illustrates the consequences of the user's choices on the narrative progression, providing feedback. Upon game completion, the system presents the ultimate storyline (Show Section 4). Showcasing the results stimulates users' desires to experience the story multiple times, to discover different outcomes or narrative paths, and to motivate players to improve their skills and formulate strategies, increasing the user's creativity and sense of achievement in storytelling. In line with [PERSON]'s (2018) exploration of narrative structures in games, particularly \"multiple ending design and plot branching,\" [23] this study further contributes to the theoretical foundation of game narrative structure. In essence, this interactive mode is crafted to deliver a diverse interactive journey, ensuring each mode is uniquely stimulating and captivating, enhancing entertainment and educational value. The inclusion of multiple endings and a dynamic event system guarantees a distinctive experience each time, heightening player engagement and satisfaction, and establishing an innovative and intellectually stimulating collaborative narrative interactive platform. Main Functions and Interface Design of Initial Co-Relay  
The main functions and interface design of the initial \"Co-Relay\" system include the main interface, story creation module, character management module, task challenge module, social interaction module, and user settings and help module. The main interface serves as the central hub of the system, providing navigation menus, user level, and point displays, a quick search bar, and notification icons for easy access to various functional modules.