Dies Irae is a sci-fi adventure crossover which includes elements from the Supreme Commander series. The story takes place in 3846, a few years after the Infinite War and the events of the first Supreme Commander. The Equestrians, living peacefully in their own dimension, have established a prototype space fleet used for research and discovery. However, things go wrong when an anomaly is detected not far from Equestria. It is up to five ponies, the crew of the E.S.S. Discovery, to discover what is occurring in the far reaches of their beloved solar system before it is too late.