The book follows Chris Zajac, the 5th grade teacher at Kelly School, one year in the elementary school. The book opens describing her as a teacher who values dressing professionally, timelines, and effort from her students, and who is very dynamic and engaged in her classroom. We also meet the students and begin to get a sense for the school and this particular class.

Mrs. Zajac’s classroom is about half American and half Puerto Rican, and about half the students qualify for free or reduced-price lunch. Mrs. Zajac receives the cumulative records (or “cumes”) for each of her students, which show their grades and behavioral issues or referrals and notes from their entire time at the school. She does not look at these records at first, letting herself form opinions as openly as possible before looking through them. She learns things quite quickly, such as which students are from wealthy families, which students may have a chaotic home life, and which students are likely to be diligent in class. She allows students to choose their desks on the first day, but then she re-arranges them based on what she has learned about them and what she thinks will be best for each student.