A planet in the endless emptiness of space, far from the warmth of any sun. And yet there are people who populate its vast caverns, living, working and loving. Since time immemorial, they have been on course for Andromeda, the neighboring galaxy of the Milky Way. This is the prophecy of the ancients, the one goal that unites them all, their cult.

But then the unthinkable happens: The journey stops because the planet enters the orbit of a mysterious object that can't be seen in any telescope. Scientists doubt its very existence, though they can't give any other explanation as to why the journey to Andromeda has come to an end.

And then the messages start.