Olive collects words. Rare words, common words, fancy words, funny words. She expresses herself by writing poetry, making crossword puzzles, and creating dictionary definitions for what she refers to as "neologisms." Her sister, Mattie, could not be more different. Mattie struggles with words and so instead prefers pictures, expressing herself through cartoons and sketches.

Despite their differences, the two girls are inseparable. Or at least, they were. After their dad moves away and Olive develops her first crush, the sisters’ dynamic changes. Olive wants to spend more time with people who aren't related to her, but Mattie doesn't want anything to change. When their dad starts acting suspiciously and Mattie’s grades begin to fall, the sisters’ relationship fractures.

Olive and Mattie must discover that love isn’t always how we envision it.