Seventeen-year-old Lorna loves her adoptive sister, Callie. But Callie can’t say “I love you” back. In fact, Callie can’t say anything at all.

Because Callie is an Iceling—one of hundreds of teens who were discovered sixteen years ago on a remote Arctic island, all of them lacking the ability to speak or understand any known human language.

Mysterious and panicked events lead to the two sisters embarking on a journey to the north, and now Lorna starts to see that there’s a lot more to Callie’s origin story than she’d been led to believe. Little does she know what’s in store, and that she’s about to uncover the terrifying secret about who—and what—Callie really is.