Day of the Dragon King by Mary Pope Osborne

Sent to ancient China, Jack and Annie are tasked with saving a book before the Dragon King can destroy it. They disguise themselves as scribes and sneak into the imperial library to complete their mission. With help from a brave scholar, they learn about the power of writing and the emperor’s fear of knowledge. The plot combines danger, culture, and clever problem-solving. It’s a journey into the heart of a civilization that valued wisdom—until it was silenced.