When configuring transmedia universes, it is necessary to design a map of contents that complies with a design of platforms and channels with its potential incidence on audience. In order to do this, we need to operate in a parallel manner between narrative displays and production design, which include the aesthetic line, technological devices and the design of potential audiences. In this paper these two broad perspectives converge, the production designer's and the storyteller's, delving into the joint processes that operate when it comes to building an architecture of transmedia contents, an operation that must be hand in hand with the corresponding technological solutions. All this is summarized in the case of Plot 28, a transmedia universe pioneer in Spanish language launched in January 2013 associated to a transmedia format (Total fiction). The creation experience interacts with the analytical and theoretical approach to offer a rather uncommon enriching perspective of the case of study. This way we will analyze, from a creator praxis, already corroborated but justified by the latest theoretical and hermeneutical approaches, narrative, interaction and gamification strategies, contents management and their scalability, the design of browsing maps, seeking the audience's empathy with the designed diegetic world. All this accompanied by data obtained from direct sources in this production and dissemination experience that may enlighten future projects. [ABSTRACT FROM AUTHOR]