This is book number 37 in the Magic Tree House series.
Merlin the Magician will not eat or sleep or speak to anyone in Camelot. What can be done? The enchantress Morgan knows who to ask
for help: young Jack and Annie of Frog Creek, Pennsylvania! The brother-and-sister team quickly head off in the magic tree house on another magical and historical adventure.
Their mission: discover one of the four secrets of happiness.
Their journey: to a land of fierce samurai and great beauty, the capital city of Edo (now the city of Tokyo), in ancient Japan in the 1600s.
Their tools: a research book to guide them and a magic wand with three special rules.
In Dragon of the Red Dawn, Mary Pope Osborne transports readers back to the splendor, rich culture, and magic of traditional Japan.