At what point did quantum physics go from being a theoretical revolution to a force capable of transforming or even destroying the world? It may seem like a complex question to answer, but it is an entirely necessary approach in times of war and polarization. The Doctor of Quantum Optics from the Autonomous University of Barcelona (UAB) and science communicator Sònia Fernández-Vidal (Barcelona, 1978) concludes the successful trilogy The Door of the Three Locks with the prequel titled The Shadow of the Two Suns (Destino). Aimed at a young audience, the author once again turns to fiction to put one of the great debates of our time on the table: what has led human beings to the development of nuclear energy and the atomic bomb? Despite being a story with fictional characters, Fernández-Vidal incorporates tangible certainties and figures of 20th-century science.