Stowaway City is an immersive audio experience that combines electroacoustic composition and storytelling with extended reality. The piece was designed to accommodate multiple listeners in a shared auditory virtual environment. Each listener, based on their tracked position and rotation in space, wirelessly receives an individual binaurally decoded sonic perspective via open-back headphones. The sounds and unfolding narrative are mapped to physical locations in the performance area, which are only revealed through exploration and physical movement. Spatial audio is simultaneously presented to all listeners via a spherical loudspeaker array that supplements the headphone audio, thus forming a hybrid listening environment. The work is presented as a conceptual and technical design paradigm for creative sonic application of the technology in this medium. The author outlines a set of strategies that were used to realize the composition and technical affordances of the system.