Night of the Ninjas

Eight-year-old Jack and his seven-year-old sister, Annie, live in Frog Creek, Pennsylvania. They are the discoverers of a magical tree house filled with books, which belongs to a magical librarian named Morgan le Fay and can transport them to the places depicted in the books. After weeks of absence, the tree house reappears in the tallest oak in the woods. Jack and Annie climb inside and find it empty except for scattered books, a glowing letter M on the floor, and a small brown-and-white mouse, which Annie names Peanut. Jack finds a note from Morgan that reads, Help me - Under a spell Find + thin[gs]. They realize Morgan is in trouble and needs them to find four items to break a spell.

Annie notices an open book with a picture of two ninjas on a mountainside in Japan. While Jack wants to read the book to prepare for their journey, Annie insists they must hurry to help Morgan. She grabs the book, points to the picture, and wishes they were there. The tree house spins and transports them to ancient Japan, landing in a tree on a mountainside next to a rushing stream. From the window, they see two ninjas, one tall and one short, standing near the water. Jack quickly reads about ninjas in the book and takes notes in his notebook. The tall ninja spots them and cries out, and both warriors dash toward the tree.

Jack and Annie realize the book with the picture of their home, which they need to return, is missing. To protect themselves, they pull the rope ladder into the tree house. Using iron bands with claws on their hands, the ninjas climb the tree trunk and enter silently. Annie bravely shows them Morgan's note. The ninjas seem to understand and lead the children down the ladder, effectively capturing them. They guide Jack and Annie to the edge of a wide, icy stream. When the children find the water too cold to cross, the tall ninja carries Jack on his shoulder and the short ninja carries Annie, wading calmly across.

On the other side, they climb the mountain, spotting torches in the valley below, which the ninjas appear to be avoiding. They enter a pine forest, where the ninjas signal for them to wait before disappearing into the shadows. While waiting, Jack reads that ninjas hold meetings in hidden caves and take orders from a ninja master. The ninjas soon return and lead them into a dark cave lit by candles. Inside, they meet the ninja master, a dark figure sitting on a mat. The master reveals that the short ninja is a woman and that the men with torches are samurai, their enemies, who are drawing near.

The master explains he cannot help them directly but gives them three rules to follow for survival: Use nature. Be nature. Follow nature. He instructs them to travel east to find their tree house and warns them that the samurai will show them no mercy. The master and the two ninjas then disappear, leaving Jack and Annie alone. Jack writes the master's rules in his notebook. To find their way, he remembers a trick from a camping book and uses a stick's shadow in the moonlight to determine which direction is east. As they descend the mountain, they are trapped between a samurai warrior coming down from above and more samurai coming up from below. Remembering the advice to be nature, Annie convinces Jack to hide behind a large rock and pretend to be part of it. The warrior passes without seeing them.

They reach the stream again but cannot find the tree house, and the water is too wild and cold to cross. At that moment, Peanut the mouse leaps from Annie's pouch. Jack remembers the final rule, follow nature, and they pursue the mouse. Peanut leads them to a narrow part of the stream bridged by a fallen tree branch. Though Jack is hesitant, Annie convinces him they can cross if they act like mice, becoming teeny and light and fast. They successfully dart across the branch. On the other side, they spot the tree house just as the samurai approach again. They hurry up the rope ladder and climb inside.

Inside the tree house, they find Peanut and the ninja master waiting. The master praises them for following the way of the ninja and gives Jack a smooth, round moonstone, which Jack realizes is the first of the four things they need. The master then hands Annie the Pennsylvania book, explaining they could not see it before because they first had to complete their mission. With the final advice to keep a kind heart, the master disappears down the ladder. Annie points to the picture of the Frog Creek woods and wishes them home.

They arrive back in their own time just as their father calls them for dinner. No time has passed. Jack examines the moonstone, the first item for Morgan's quest. Annie decides to leave the mouse on the glowing M on the floor. As Jack kisses the mouse goodbye, he notices its eyes look old and wise. They climb down the ladder and head home, moving silently through the woods like the shadow warriors they have become.