Orientation in public environments is a critical skill for new arrivals, yet also one that is usually only learned gradually through trial and error. This paper suggests the use of pervasive augmented reality (AR) for the design of a serious game that teaches navigational skills in a public environment. Many AR scavenger hunt games confront players with new environments by default, however they rarely focus explicitly on teaching navigational skills. We propose a concept that utilises augmented reality techniques for increased immersion and motivation, while upholding the real-world sense of presence for an easy transfer of orientation skills to everyday life. For this purpose, we implemented a first prototypical serious game in the form of an AR scavenger hunt. A preliminary evaluation regarding its usability produced promising results. As such, the prototype constitutes a first proof of concept. In future iterations, it will be further developed as an adaptive AR serious game, and evaluated in respect to its efficacy in teaching orientation and navigation skills.