Crashed pilot Henry Johnson wakes up on another planet, many galaxies away, after being saved by an ancient race who needs his help. Henry is given a military starship, an army of drones, and telepathic abilities to police the universe.

For all their advanced intelligence, the aliens need Henry for his uniquely human ability to know when to kill for the right reasons. This new world is full of action and adventure, but Henry treasures his memories of Earth. For ten days, every ten years, he is allowed to go to Earth-as long as no one learns his secret. He is there to remember what it means to be human. But on this trip, nothing goes according to plan.

Henry finds Earth on the brink of World War III, and he struggles to resist using his superior mental and physical abilities to stop this catastrophe. But then he falls for Anna Summers, a beautiful Hollywood starlet. They spend every one of his limited days together. The two of them must stop a war, fight invaders, and figure out how their love fits into this giant universe.

Even in a galaxy a trillion miles away, there's no place like home.