We present a system that augments live presentation videos with interactive graphics to create a powerful and expressive storytelling environment. Using our system, the presenter interacts with the graphical elements in real-time with gestures and postures, thus leveraging our innate, everyday skills to enhance our communication capabilities with the audience. However, crafting such an interactive and expressive performance typically requires programming, or highly-specialized tools tailored for experts. Our core contribution is a flexible, direct manipulation UI which enables amateurs and experts to craft such presentations beforehand by mapping a variety of body movements to a wide range of graphical manipulations. By simplifying the mapping between gestures, postures, and their corresponding output effects, our UI enables users to craft customized, rich interactions with the graphical elements. Our user study demonstrates the potential usage and unique affordance of this mixed-reality medium for storytelling and presentation across a range of application domains.