Interactive storytelling opens exciting possibilities to personalized narrative creation, providing a more compelling and immersive experience than traditional narratives. In this work we propose a creative framework in which the author can specify story characteristics (such as genre or complexity) on a story structure in order to generate interactive stories tailored to personalized constraints. The story generation model combines a branching story structure with a planning algorithm that filters and recombines story fragments based on characteristics, generating a high-level interactive scenario that satisfies all authorial constraints, and provides sufficient abstraction from the technical implementation. The scenario is then simulated in a real-time storytelling system, featuring autonomous characters and camera control. As a demonstration of our approach, we have authored an interactive narrative based on the Brothers Grimm fairytale "Godfather Death."