JACK AND ANNIE AND THE NINJAS!
A spell has been cast on Morgan Le Fay and she needs Jack & Annie to retrieve some items to help her. The Kids must use the Magic Tree house to travel back to ancient Japan to find the clues to the latest mystery. They encounter some Ninja Warriors who turn out to be the good guys and the Ninja Master assists the kids on their quest. But they soon come under attack by a horde of Samurai Warriors, who threaten their mission.This book actually starts a new story arc that will play out over books #5 - 8 in the series and is called the Mystery of the Magic Spell. I like the way Mary Pope Osborne has written these books to be stand alone adventures and yet all four to be part of one 4 book story arc. This one loved at a bit of a slower pace than some of the previous books. There wasn't the chills as their were in Mummies in the Morning, for example. But still a solid effort with excellent illustrations by Sal Murdocha.