Ruby Palmer is still stuck on a planet of alien robots. But she's made a discovery that means, more than ever, she needs to get home.

But the robots want her to stay. She's already helped them beyond their wildest imagination, but they need a human programmer who can correct the unknown errors no algorithm can predict. Some of them will do just about anything to keep her there. Others don't want her interfering lest she uncover their secrets.

If Ruby doesn't get home, people will die. But if she leaves, the robots will certainly continue to malfunction. Can she convince these crazy foolish robots that getting her home is the solution to both their problems?