In the middle of an intergalactic war, one of the best pilots in the stellar fleet witnesses helplessly the destruction of the entire fleet and, with it, the annihilation of all mankind. When the oxygen in his destroyed ship ran out, he only reproached himself for not having been able to at least die like a hero. However, without knowing why, his soul returned in time to the day of his entrance exam at the academy. This time Eneas would save his life, his mother's life, and everyone he could save. Armed with an inhuman ability to pilot, he will make the most of his mecha, the Phoenix named Uroboros, changing history of the universe forever.