From the visionary author of two 2021 Newbery Honor Books, comes a high-seas adventure set in a Thai-inspired fantasy world.A young woman struggles to unburden herself of the past and chart her own destiny in a world of secrets. As assistant to Mangkon's most celebrated mapmaker, 12-year-old Sai plays the part of a well-bred young lady with a glittering future. In reality, her father is a low-life conman - and the truth could ruin her. Sai seizes the chance to join an expedition to chart the southern seas, but she isn't the only one aboard with secrets. When Sai learns that the ship is heading for the fabled Sunderlands - a land of dragons, dangers and riches beyond imagining - she must weigh the cost of her dreams.A compelling and suspenseful middle-grade fantasy adventure.