Thirteen-year-old Maya, who has spent her life at sea with her marine biologist parents, yearns for a normal life, but when a storm washes her parents overboard, life becomes anything but normal for Maya, her younger brother and baby sister, as they land at a mysterious, uncharted island filled with danger.

Penny Nelson grew up listening to her older sister and brother recount their adventures in Tamarind, a magical island not found on any map, but she sometimes she can't tell which of her memories are hers and which are theirs.