Eva and Addie are sisters whose souls were born into the same body like everyone else around them. However, instead of "settling" and letting the recessive soul, Eva, naturally fade away, Eva hangs on to life even though she is trapped in Addie's mind. Only Addie knows she is still there because if anyone knew, she'd be labeled a hybrid and locked away. But if the girls could find a way for Eva to move again, they would risk everything.
