Price of Imperium

The Imperium is on the brink of annihilation, and only one person can save it. 

After centuries of peace, the Enemy has returned, and the only one who can unlock the Imperium's last line of defense is the rightful emperor. Unfortunately, the throne has been empty for a decade. 

The sole remaining heir is rumored to be on a backwater planet where no one has heard of the Imperium. Can he be found before the Imperial system is dissolved and the ships of the Imperial Guard are sent to the Wreckers? 

Meanwhile, on Earth, a homeless man dreams of the stars. 

Who will be willing to pay the Price of Imperium?