The main character is Pan Gamma Vi Gen. He is the captain of the legendary black vessel. Pan Gamma Vi Gen is lazy and clumsy -- that is him when is resting. But once Pan decides to work, he is the best man available. Pan says things that normal people can hardly understand. And he doesn't say much, he only gives lots of clues.
Everything starts when Captain Pan let Mia and Tuban Sanoo be aboard. Mia is a princess of a fallen country and Tuban is the best, people say, swordsman as well as strategist. Although Pan Gamma Vi Gen is the main character, it seems Pan, Mia and Tuban are the main characters as Mia and Tuban appear in all episodes. Mia is looking for science to restore her county, Ontana. Tuban is protecting Mia as the will of someone Tuban trusted. Pan Gamma Vi Gen agreed to take Mia to where she could locate the science in exchange of her virginity. (Don't get Pan wrong here, I believe he meant something else but at this moment, Mia's virginity is all I can guess.)