Fictions for virtual reality are mostly conceived either in an entirely virtual environment or in a real environment with very little transformation. It is infinitely rare to find examples of sets designed and built specifically for a 360°e xperience. Building, rather than remaining purely virtual, raises complex questions about the organization of a``space to play'' and therefore how to produce a narrative for immersion and create a 360°film grammar.We thus have created a first 360°set for the famous director Marc Caro, for whom the question of off-screen raised a very complex technical problem regarding lighting, visual effects, staging, blocking and acting. In this contribution we will show how this was solved and why the definition of a 360°narrative grammar is crucial. These are important intricacies that place the user-spectator in the optimal conditions to appreciate the experience.