If one would attempt to summarize game-based learning with a single word, "motivation" is likely a good candidate. Game-based learning is all about motivating users (no matter at what age) to learn by entrapping them with a desirable gaming experience. This, however, is not trivial. Particularly when focusing on adolescents who are used to the enormous quality of commercial, non-educational games, the educational games must be able to keep up with that quality to fully capitalize playing/learning motivation. A crucial factor in this context is personalization - is tailoring learning experiences to the learners' requirements, preferences, and abilities. The underlying idea is quite simple. The motivation through the game must be complemented with adequate learning paths; the learner shall neither be overburdened or frustrated, nor under-challenged or bored. Only if the gameplay demands and the educational demands are at an appropriate level, a "flow" of gaming and learning can be achieved. The European research project 80Days endeavours such personalization by combining frameworks of psycho-pedagogical adaptation, interactive storytelling, and emergent game design. Essentially, the idea is to assess learning progress in a non-invasive way by monitoring the learner's actions in the game. In turn, we provide the learner with tailored support and interventions as well as personalized learning paths by assembling a chain of suitable learning situations in the game. In the context of a game, this is not trivial since individual learning paths mean unavoidably having individual paths through the game and its storyline. To merge these two (sometimes competing) strands, we combined technologies of educational adaptation and technologies of interactive storytelling and story generation.