Midnight on the Moon

Mary Pope Osborne's Magic Tree House novel Midnight on the Moon follows eight-year-old Jack and his seven-year-old sister, Annie, on the final leg of a quest to free their friend Morgan le Fay from an enchantment. In earlier adventures, the siblings discovered a magic tree house in the woods near their home in Frog Creek, Pennsylvania, that can transport them to any place pictured in its books. The tree house belongs to Morgan le Fay, a magical librarian from the time of King Arthur who travels through time and space collecting books. After discovering that Morgan has been placed under a spell, Jack and Annie set out to find four special things, each beginning with the letter M, that will break it. Accompanied by a small mouse named Peanut, they have already retrieved a moonstone in old Japan, a mango in the Amazon rain forest, and a mammoth bone from the Ice Age. They now need only the fourth M thing.

Annie wakes Jack at midnight, insisting that the full moon might help them on their quest. They walk through the moonlit streets into the Frog Creek woods and find the tree house shining in the silver light. Inside, moonlight illuminates the letter M on the floor and the three collected items. Peanut sits on an open book whose cover reads Hello, Moon. Annie is thrilled at the idea of visiting the moon, but Jack insists it is impossible without equipment, since the moon has no air and its temperatures are deadly. He points to a picture of a dome-shaped structure and wishes to go there. The tree house spins and then falls absolutely silent.

They find themselves inside a large, round, windowless white room with no one else present. Jack reads that a moon base was built on the moon in the year 2031, and its domed top slides open to allow spacecraft entry and exit. He realizes the book must come from the future, meaning Morgan traveled forward in time to borrow it. Jack copies a map of the base into his notebook, but when he looks up, Annie has already left to explore.

Jack follows her through the base to an airlock. Through a window in the door, they see a rocky gray landscape of craters and mountains under an ink-black sky. Annie reaches for the OPEN button, but Jack stops her, reminding her there is no air outside. The book explains that daytime heat reaches 260 degrees and that spacesuits provide air for two hours. In the storeroom, they suit up in the smallest spacesuits, which include air tanks and helmets with two-way radios. Jack reminds Annie they have only two hours and must find the fourth M thing quickly. They cycle through the airlock and step out onto the moon.

Jack takes in the fine gray dust and countless footprints that will never wear away because the moon has no rain or wind. Far away in the black sky, Earth glows blue and white. Annie begins bounding across the surface in giant leaps. Jack reads that a person weighs only one-sixth as much on the moon due to its low gravity and joins her in leaping. He slips at the edge of a shallow crater and falls; his bulky suit makes it impossible to stand alone, and Annie has to pull him up. In the crater, they find a moon buggy with four huge wheels. Despite Jack's protests that they cannot drive, Annie argues the buggy will help them search faster. Through trial and error, she figures out the controls, and they zoom off across the surface trailing clouds of dust.

Annie drives the buggy through a mountain pass onto even rockier terrain. The landscape is colorless and barren until they spot an American flag and a telescope. They stop at the historic site of the first moon landing, where Annie reads aloud the plaque left by the first astronauts in July 1969, declaring they came in peace for all mankind. Jack writes their own message, declaring themselves the first kids from Earth to visit the moon in peace for all children. They leave it by the flag, knowing no wind or rain will ever disturb it. Jack grows anxious about their remaining air. Annie peers through the telescope and spots something flying in the distance: a giant figure in a spacesuit.

Jack insists they return to the base. He takes the wheel and speeds back toward the mountain pass, but a meteorite, a rock from outer space, crashes into the narrow pass and blocks their path. Annie takes giant leaping steps and clears the rock. Jack follows but lands facedown in the dust and cannot get up in his bulky suit. Annie tells him over the radio that she has also fallen. Neither can stand.

As Jack worries about their dwindling air, Annie whispers that the moon man is standing above her. She tells him they come in peace. He silently helps her up, and she then pulls Jack to his feet. The moon man wears a metal visor hiding his face and carries a giant jet pack on his back. Because he is not connected to their radio, Jack writes a message in his notebook introducing himself and Annie. The moon man takes the notebook, carefully draws a pattern of stars, and flies away over the mountains. Annie points out that the drawing might be a map, and "map" starts with M. They tentatively conclude this is the fourth M thing.

Jack and Annie hurry back to the base on foot as their air runs low, reaching the airlock just in time. Back in the tree house, Jack places the star map on the letter M alongside the other three items, but the Pennsylvania book they need to travel home is missing, suggesting the map is not the right thing. Jack uses his pencil to connect the stars, and the resulting constellation looks like a mouse. He and Annie both realize that the fourth M thing is a mouse: Peanut herself. Together they chant, "Moonstone, mango, mammoth bone, mouse." A blinding, whirling light fills the tree house. When it clears, Peanut is gone, and Morgan le Fay stands before them.

Morgan thanks them for freeing her and confirms she was Peanut the entire time. She explains that the spell could only be broken on the moon and that they could have broken it the moment they arrived, without ever leaving the base. Annie realizes Peanut had been trying to tell them this by running back and forth on the M. Morgan reveals that the moon man visited the base while they were exploring and that she communicated with him by squeaking, just as she had with helpers on previous quests. She says certain wise ones understand the language of little creatures. She also confirms she was the one turning pages in the books to guide them. Morgan reveals that Merlin cast the spell that turned her into a mouse, but she dismisses him as "not that great" because he does not know she has two brave friends.

Morgan gives them the Pennsylvania book, and Annie wishes them home. The tree house returns them to the Frog Creek woods at midnight. Morgan tells them she must return to Camelot and cannot stay. She thanks Jack for his love of knowledge and Annie for her belief in the impossible, brushing moondust from Jack's cheek. They climb down, and the tree house vanishes with Morgan. Walking home through the cool midnight air, Annie wonders if the moon man might be an alien from another galaxy. Jack dismisses the idea for lack of proof, but Annie reminds him they were in the future. Recalling Morgan's words about the universe being filled with wonders, Jack whispers goodnight to the moon man and closes the door.