Due to the evolution of the technology, Game-Based Learning (GBL) offers new features to support the students in an engaging and motivating way of learning. Several aspects are changing. First of all, we want to address the collaborative learning aspects. Multiplayer GBL environments are thus interesting for us. We are also interested in mixed reality approaches, since we believe that a global learning activity must not take place entirely in the virtual environment. We rather prefer to split the global learning session in several smaller activities taking place alternatively in virtual environments and in real environments. In the real environment, the activity may be supported by new devices (as tabletops for supporting collaborative activities). This allows an increasing use of pervasive and geolocated games. These games mix activities in the real world with the use of technologies and typical mechanics from video games. This paradigm offers new challenges in the interactive experience and helps to create new mechanisms for teaching educational contents. However, these approaches often lead to somewhat complex scenarios, and the learners can be disturbed. We therefore need to link naturally the different activities. Including stories in the description of a game or a set of activities is a good way to motivate the participants. Narrative benefits immersion in virtual worlds and helps to teach through the use of video games. However, designing this kind of stories is a complex task due to the interactive feature of video games. These stories are different for each player because they can change the events of the story through their actions. Therefore, writers of the story and designers of the game must develop an interactive story that is always good even though the decisions of the player. In the present work, we propose a set of techniques to design and evaluate an Interactive Story to be included in an educational pervasive game. Starting from the educational activities of the game, it is possible to design the structure of the story, improve it, write it and evaluate if it is a good story or not. This evaluation allows the game to change the story in real time along the playtime.