The Legion of Doom led by Grogar have planned to conquer Equestria and destroy its protectors. However, without any warning, an old acquaintance of Grogar waylays him and his legion and sends them to a place they never thought they would see or encounter except for the ram. With an unusual turn of events and an odd alliance of ancient creatures occurring, the Legion must work together to fight this new threat and the newfound power that could end their existence.