All Eva ever wanted was the chance to be herself. But in the Americas, to be hybrid—to share your body with a second soul—is not tolerated past childhood. Now Eva and Addie, her sister soul, are constantly on the move, hiding from the officials who seek to capture them. But the tide is changing. A revolution is brewing, and people are starting to question the hybrids' mistreatment.

Then Marion, an ambitious reporter, offers Eva and Addie a daring proposal: If they go undercover and film the wretched conditions of a hybrid institution, she will not only rescue them, she'll find a way to free Jackson, the boy Addie loves. It's risky, and Eva will have to leave Ryan and her friends behind, but if she succeeds, it could also tip the scales forever and lead to hybrid freedom.

As Eva and Addie walk into danger, they cling to each other and the hope of a better future. But the price they might pay is higher than they ever could have imagined.