Magic Tree House: #5 Night of the Ninjas by Mary Pope Osborne
From Random House Books for Young Readers:
The #1 bestselling chapter book series of all time celebrates 25 years with new covers and a new, easy-to-use numbering system!
Have you ever met a real live ninja? Jack and Annie do when the Magic Tree House whisks them back to ancient Japan, where they find themselves in the cave of a ninja master. Will they learn the secrets of the ninja? Or will the evil samurai warriors get them first?
Did you know that there’s a Magic Tree House book for every kid?