It had been eighteen years since they'd seen their home world.  Eighteen years since the earth had lain before them vibrant and blue. They had come home, and brought with them the water of life, salvation for a world in need. They'd left a desperate band of men with a mission, journeyed the stars as beggars, then thieves, and ultimately destroyers to return home to be heroes.

'Orbital control, this is the Lazarus on return approach, we're inbound heavy looking for our vector, over'

Nothing but silence greeted their request.

Earth was being consumed by a terrible plague when they had left, a plague that destroyed the infected from the inside.  The doctors needed fresh blood, in great quantities in order to transfuse, and to synthesize the antibodies that had been cleaned from their blood through the generations. They had dug up a horrific judgement of a great many years ago, and no one was immune anymore. A disease their ancestors would have thought nothing of now stood to annihilate them to a man.  How far they'd come, and how quickly they'd fallen.

The mission of the Lazarus was to visit the worlds colonized over the generations, to collect blood from the inhabitants of these civilizations the earth had birthed amongst the stars, and to bring it back to save their ancestral home world. The people on these worlds had forgotten who had given them life, and they were reluctant to help when asked to share their blood.  Maybe one in twenty would offer up a litre willingly, but the men on the Lazarus found that everyone had 5 litres to spare if they weren't given the choice. These roving collectors of the water of life were prepared to sacrifice these insignificant worlds in order to save their home.  They could be colonized again, but the survival of their planet of origin must be assured.

Almost four million litres of blood filled the belly of their ship on its return voyage, three quarter of a million lives sacrificed for the sake of the human race. They had become masters of its retrieval, machines of exsanguination gone mad, but justified in doing god's work, and now they were home.

'Orbital control, this is the Lazarus, are you reading us?'

The silence mocked the hero's return.

'Orbital control, we're on an urgent approach, we have no sensory data on proximal traffic, we're bypassing your authority and dropping into lower earth orbit.'

The Lazarus rolled into its approach, the crew fastened safely in their harnesses as the giant craft burned through the upper atmosphere in a red hot blaze of glory before leveling off to cruise above the planet in the direction of its home landing field.

'Cheyenne control, this is the Lazarus on return approach.  We've cleared the upper atmosphere and are requesting an airway inbound. Over.'

No signal greeted the pilot, there was no reply at all.

They slowed and gave up altitude gradually, straining eyes through view ports and scrutinizing the sensors to see what would greet them below. Across Iowa and Nebraska they saw nothing, no life signs, picked up no radio signals or navigational beacons, there was nothing but barren ground and silence.

As they reached the border of Wyoming, the radio crackled to life first, followed by a video transmission that filled the view screen.  The crew turned from their tasks and windows to watch a shrunken man, gaunt and lesioned as he cleared his throat and spoke.

'Lazarus crew. If you are receiving this transmission, I'm afraid you are too late.  The disease has accelerated beyond our ability to contain it, and most of the population of this earth has succumbed. Do not land your craft. Do not take on any material from this earth. The planet must remain in quarantine. This planet has survived the loss of its inhabitants before, it will rise again without us.'

The man paused, eyes closing for moment before taking a breath and continuing.

'Lazarus crew, the only hope for humanity lies now with the colonies.  You must go to them, help them, protect them, provide transport between them that they may share knowledge and resources and assure the future of the human race. If you are here, then it's because these colonists gave freely of themselves in order to save us, you must now give back to them in order to save us all. The future of the human race lies in your hands, good luck, and god speed'

As the transmission ended, silence once again filled the cabin. Through this silence everyone onboard could feel the cries of the lives they carried, litre by litre in the belly of the beast that was all that remained of the human race.