Male and females are separated. A giant, seventy-five foot wall divides them. Wren never even thought about going over the wall, until her nephew was born. When a baby girl is born, the doctors put a drug inside her called 'The Making'. This drug allows a baby to start developing inside of them when they hit the age of 20. If it's a girl, this cycle continues. If it's a boy, he has to go over the wall. The mother gets three days with her son and on the third day, they put him into The Lift and he is taken to the male side. Wren's sister had her baby. But it's a boy. Abel. During the three days, Wren feels like she connected with Abel. But the three days isn't enough. He was sent over the wall and that night, Wren couldn't sleep. She misses her nephew. So she did the unthinkable. She went over the wall. Now that she's over, she must find Abel. She meets a boy named Sawyer and he helps keep her secret. But Wren doesn't like the way this world is anymore. She wants to take Abel and leave. But that's not going to be easy when there's a boy at every turn.