An invisible, uncrossable physical barrier encloses the Unified States. The Line is the part of the border that lopped off part of the country, dooming the inhabitants to an unknown fate when the enemy used a banned weapon. It's said that bizarre creatures and superhumans live on the other side, in Away. Nobody except tough old Ms. Moore would ever live next to the Line.

Nobody but Rachel and her mother, who went to live there after Rachel's dad died in the last war. It's a safe, quiet life. Until Rachel finds a mysterious recorded message that can only have come from Away. The voice is asking for help.

Who sent the message? Why is her mother so protective? And to what lengths is Rachel willing to go in order to do what she thinks is right?