Heart of the Valkyrie

In a future among the stars, the origins of mankind have all but faded into the past. Nathan and his crew aboard the Valkyrie, an extraordinary but ancient ship, enjoy the freedom of the outer systems, away from the despotic rule of the Quanios Empire. But when they suddenly find themselves saddled with an equally extraordinary teenage girl, Sybille, who is now being sought by the Empire, things take a very unexpected turn.
They are thrown into a desperate race to locate the lost planet of mankind's origin. To stop the Empire, they must solve the mystery of Sybille's past and locate Earth first, or it could mean the end of freedom for the known galaxy.