Told through a series of interrelated documents (including emails, text messages, newspaper clippings and blog posts), Annabel Smith’s interactive digital novel The Ark epitomises the contemporary hybridity of the dystopian genre. Designed to be fully immersive, the story can be engaged with across media, enabling readers to ‘dive deeper into the world of the novel’ and challenge how they experience dystopian texts. Taking a Text World Theory perspective, I examine the implications of this challenge, investigating the impact of transmedial storytelling on world-building and exploring the creative evolution of dystopian epistolary more broadly. In analysing both the ebook element of The Ark and certain facets of its companion pieces (which take the form of a dynamic website and a smartphone app), I investigate the creation of the novel’s text-worlds, considering the process of multimodal meaning construction, examining the conceptual intricacies of the epistolary form and exploring the influence of paratextual matter on world-building and construal. In doing so, I offer new insights into the conceptualisation of ‘empty text-worlds’, extend Gibbons’ discussions of transmedial world-creation and argue for a more nuanced understanding of dystopian epistolary as framed within Text World Theory.