I am lucky just to be alive. Eva was never supposed to have survived this long. As the recessive soul, she should have faded away years ago. Instead, she lingers 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, Eva and Addie find shelter with a group of hybrids who run an underground resistance. Surrounded by others like them, the girls learn how to temporarily disappear to give each soul some much-needed privacy. Eva is thrilled at the chance to be alone with Ryan, the boy she's falling for, but troubled by the growing chasm between her and Addie. Despite clashes over their shared body, both girls are eager to join the rebellion. Yet as they are drawn deeper into the escalating violence, they start to wonder: How far are they willing to go to fight for hybrid freedom? Faced with uncertainty and incredible danger, their answers may tear them apart forever.