On the return trip of a routine voyage to Mars, astronaut and astrophysicist PJ takes an unscheduled stop on the moon to bury his best friend. While saying the funeral rites, PJ witnesses a catastrophe that will irrevocably change his universe.
Now, left completely on his own, he must somehow find a way to survive the cold, endless expanse of space. But amidst depleting resources and a futile search for help, he discovers that he may have an even more dangerous adversary he needs to face—his own mind.
With a tremendous cosmic intellect, PJ can truly understand the desperate situation he is in. And as the days pass and his mind begins to turn on him, he learns what it actually means to be alone.