Thirteen-year-old Joey Willis is used to being left out of conversations. Though she's been deaf since the age of six, Joey's mother has never allowed her to learn sign language. She strains to read the lips of those around her, but often fails.

Everything changes when Joey meets Dr. Charles Mansell and his baby chimpanzee, Sukari. Her new friends use sign language to communicate, and Joey secretly begins to learn to sign. Spending time with Charlie and Sukari, Joey has never been happier. She even starts making friends at school for the first time. But as Joey's world blooms with possibilities, Charlie's and Sukari's choices begin to narrow--until Sukari's very survival is in doubt.