There is a reality that surrounds us, but which, even today, remains invisible. Today, it is taken for granted that our understanding of the physical world comes through the use of sophisticated mathematical tools. What is DEFINITELY less obvious is ‘how’ this happens. There are at least two basic ingredients: mathematical models, which represent reality in a simplified way, and computational methods for calculating the solutions of these models. In order to understand what happens in the combination of these two ingredients, one has to deal with a high degree of abstraction. The standard solution to this dilemma in science communication is to skip this process and tell the result directly: the molecule of the new drug, the ‘exotic’ material, the intelligent fluid. In this issue, produced in collaboration with CECAM– Centre Européen de Calcul Atomique et Moléculaire, we’ve tried to explain the ‘how’ instead. Inspired by the Centre’s projects of excellence, Giovanni Eccher and Sergio Ponchione have created a story in which, for the first time, an attempt is made to explain the philosophy behind the models and the use of the HPC, the powerful secret ingredient of high-performance computing.