Seikai no Monshou
Based on a sci-fi novel series, Crest of the Stars (Seikai no Monsho) is the first installment in this sci-fi saga. The story follows Jinto, a young prince, whose world was taken over by the largest Empire in the Galaxy: The Abh. Jinto's father handed their world over to the Abh in exchange for a standing in the Abh Empire. As a result, Jinto became a prince and was shipped off for an Abh Education. Later he meets a princess of the Abh Empire, Lafiel, whom he quickly befriends despite her cold exterior. The Abh empire is plunged into war and the story continues from there...
an extended description!