Life for Dinora Diaz, DeeDee for short, is full of D’s. Missing her dad, who’s disappeared. Being diagnosed with diabetes. Feeling dumb in fourth grade at her new school, which she transferred into—leaving behind Sandro Zapote and all her other friends in Miss Hamilton’s class—after her family’s trailer burned down. It’s so many D’s that DeeDee’s sure she’ll never really fit in, much less find the perfect best friend she’s always wanted.

Then DeeDee meets River. He’s a lot like her: River loves skateboarding, art, and dancing, just like she does, and he misses his dad, too. But they’re also different: while DeeDee’s still struggling to adjust to life with diabetes and has sworn off her Mexican heritage to get back at her dad for leaving, River seems to have totally adjusted to—even learned to love—being deaf. River promises to help search for DeeDee’s dad and to compete with her in the spring skateboard exhibition at their local skate park. Finally, DeeDee has something to look forward to.

But when River transfers into DeeDee’s fourth grade class, DeeDee makes a huge mistake, putting not just the exhibition, but her entire friendship with River, on the line. Now she has to make a choice: stand up to her classmates and accept being an outsider, or give up her best friend for good? To keep the best friend she’s always wanted, DeeDee will have to learn to love difference—not just River’s, but also her own.