When Mac first opens his classroom copy of Jane Yolen's The Devil's Arithmetic and finds some words blacked out, he thinks it must be a mistake. But then when he and his friends discover what the missing words are, he's outraged. Someone is trying to prevent kids from reading the full story. But who? Even though his dad tells him to not get so emotional about a book, Mac has been raised by his mom and grandad to call out things that are wrong. He and his friends head to the principal's office to protest the censorship, but her response doesn't take them seriously. So many adults want Mac to keep his words to himself. Mac's about to see the power of letting them out.