The Line Series by Teri Hall

An invisible, uncrossable physical barrier encloses the United 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... moreAn invisible, uncrossable physical barrier encloses the United 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? less

After crossing the Line, Rachel finds herself in a world where survival is never guaranteed - a world where bizarre creatures roam the woods and people have strange abilities. Everything has gone to ruin Away and the survivors have banded into warring clans. Rachel finds her father being held prisoner by a tribe of Others, and she and her new friends set out to rescue him... moreAfter crossing the Line, Rachel finds herself in a world where survival is never guaranteed - a world where bizarre creatures roam the woods and people have strange abilities. Everything has gone to ruin Away and the survivors have banded into warring clans. Rachel finds her father being held prisoner by a tribe of Others, and she and her new friends set out to rescue him. But when they cross back over the Line, Rachel and Pathik make a foolish decision, bringing them into further danger that can only be resolved with an unthinkable sacrifice. An adventure filled with life-and-death choices, dark conspiracies, and heart-poundingly suspenseful moments, this sequel delivers. less