As the recessive soul, Eva wasn't supposed to survive this long, lingering in the body she shares with her sister soul, Addie. When the government discovered the truth, they tried to "cure" the girls, but Eva and Addie escaped before the doctors could strip Eva's soul away.

Now fugitives, they take shelter with a hybrid resistance movement. Despite growing tensions between Eva and Addie, they both throw themselves into the cause. Soon they've joined a splinter group willing to resort to questionable methods . . . but as Addie and Eva fall ever deeper into their plans, the girls must decide how far they're willing to go to fight for their new lives. What they thought was the solution to their problems just might be the thing that destroys everything—including their bond to each other.