We introduce STAGE-N (Scenic Theater with AI-Generated Environments and Narratives), a novel genre that combines immersive theater, real-time AI content generation, and interactive performance technologies. This interdisciplinary approach integrates virtual reality (VR), augmented reality (XR), motion capture, and generative artificial intelligence to create dynamic theatrical experiences where audiences can actively participate in narrative development. The core innovation lies in our "generation tags" system — real-time metadata markers that enable dynamic content creation during live performances. Our framework supports multiple environment types (metaverse, VR spaces, game engines, and XR-enhanced physical spaces), various content formats (classical adaptations, fan fiction, improvisational theater, and interactive narratives), and different levels of audience immersion. The system captures multi-modal data including movement, voice, scene logic, and environmental assets to generate theatrical content, educational materials, and hybrid media in real-time. This paper presents the theoretical framework, technical architecture, and potential applications of STAGE-N, demonstrating how generative AI can transform traditional theatrical practices while preserving the essential human elements of live performance.