The Galactic Empire under the leadership of Reinhard von Müsel emerged victorious in the Fourth Battle of Tiamat, crushing the Free Planets Alliance. This earned Reinhard a hero's welcome upon his arrival at the Imperial capital of Odin and a promotion to High Admiral, along with the coveted title of Count von Lohengramm. Meanwhile, Yang Wen-li, a key figure in the Alliance, returned unnoticed to the capital of Heinessen, where he reunited with his friends. Despite their recent triumphs, Reinhard and Yang's respite is short-lived. Duke Otho von Braunschweig, motivated by his own political agenda, urges the Imperial High Command to order Reinhard to invade the Alliance with his twenty thousand ships. Upon learning of this scheme, the Alliance government responds by deploying three fleets, totaling forty thousand ships, to recreate the legendary Battle of Dagon. However, Reinhard has a clever plan that even Yang can see through, and he is outnumbered two-to-one. The question remains: will Yang be able to warn his superiors in time to prevent disaster?