"What's Left of Me" by Kat Zhang is a story set in an alternate world that is very much like ours except for that each individual is born with two souls in their body. The main character is Eva who shares a body with Addie. They live in their version of the United States where being a hybrid is illegal. Hybrids are people who maintain two souls into adulthood. In much of the world this is normal, but in the United States, the recessive soul is expected to fade away by age 10 at the latest.
I think this is an excellent premise. This was a 3.5 out of 5 star book, and the plot premise was definitely the best thing about it. Beyond that, the book was so-so. The plot in general was good but not completely unique, believable but I wasn't immersed. The characters were interesting but not fully developed; it was hard to feel a strong empathy for any of them. There was a vague theme about the definition of being human, but again, it wasn't well fledged out. The setting was weird and made me want to know more, but I was still dissatisfied at the end of the book.
It seems that this is going to be the first book of a series, The Hybrid Chronicles. I will definitely try the second one. Perhaps that is the point of not fulfilling my curiosity too much. At the same time, I wish I would have been given more.