Emeraldas navigates the sea of stars—and swears to do so until the flame of her life is extinguished. Aboard her ship, the Queen Emeraldas, she sails in search of a certain object, and along the way encounters the passions and tragedies of those who dare brave the infinite reaches of space.

(from ebookjapan):

On the planet Jera, a young woman met her lifelong friend, a ship named the Queen Emeraldas. Huddled together and covering for each other, they set off on a journey through space...

No one knows why or what they continue to wander the universe in search of. On the red sands of Argyre, Emeraldas meets a boy named Hiroshi Umino, who has lost his spaceship. Emeraldas feels some kind of strong fateful bond with this boy who has an indomitable fighting spirit...

Official English