The Strangers by Margaret Peterson Haddix follows three siblings—Chess, Emma, and Finn Greystone—who discover a shocking news story about three kidnapped children with their exact same names, birthdays, and appearances. When their mother mysteriously disappears after the news breaks, the kids are left with a stranger and must uncover the truth about their own identities. They find coded notes their mother left behind and realize they must solve a dangerous puzzle that connects them to another world. The story is a thrilling mystery about family, secrets, and courage.