Marty has hopes that his brother is still out there somewhere, and he is determined to get to him. He illegally deals in mirrors to gather the funds he needs to find his brother. The penalty for such dealings is exile, which essentially equates to death with the Beings who are out there. When he is caught by the mayor's son, and they are exiled together, their journey becomes even stranger than the lone island they came from, and bigger questions and answers arise.
To avoid spoilers, I will be somewhat vague. The plot was quite creative with plenty of twists and turns. A lot of questions come up earlier and they are all answered by book's end. The strongest part of the book is the main character, Marty, and how he lives with his OCD. The book does a great job of describing this as well as his past therapies/treatments, and the portrayal really brings OCD to life for people who do not have this disorder. Given the setting/other events, this may seem like a smaller part of the story, but I found it to be the most poignant and the biggest takeaway from a solid sci-fi/dystopian read.
Overall, this is a great YA sci-fi read- not only for the page-turning, fast-paced, and mind-stretching plot that keeps the reader hooked, but also, mainly, for the powerful #ownvoices portrayal of a main character with OCD. Highly recommend picking this one up.