World at War, 1944

This is the first Super Edition in the Magic Tree House series, a children's fantasy adventure series in which siblings Jack and Annie travel through time using a magic tree house connected to the legendary realm of Camelot. They have been aided on past adventures by Teddy and Kathleen, two young enchanters, and by Merlin, Camelot's magician.

One summer afternoon in Frog Creek, Pennsylvania, Annie calls her brother Jack outside to see a pigeon that followed her home. They notice a tiny red canister on its leg, identifying it as a carrier pigeon. Annie concludes the pigeon came from another time, sent through the tree house. They race to the Frog Creek woods, where they find a note from Teddy, their friend and apprentice sorcerer. He asks them to come to Glastonbury, England, immediately, writing that he and Kathleen need help in one of the darkest hours of history. Jack points to the words "Glastonbury, England," activating the tree house's magic.

At the ruins of Glastonbury Abbey, Teddy explains that the date is June 4, 1944, and World War II has raged for nearly five years. Merlin sent Teddy and Kathleen to London to inspire British leaders. Kathleen used magic to make them appear older, and they impressed officials, including Prime Minister Winston Churchill, who inducted them into the Special Operations Executive (SOE), a top-secret spy organization conducting undercover missions in Nazi-occupied countries. Kathleen left for a mission in France three weeks ago and has since disappeared. Her coded message requests the Wand of Dianthus, a magical wand, and a rhyme to unlock its power. The message also references "Sir Kay's grave," an Arthurian code clue Teddy interprets as the town of Caen in Normandy, along with cryptic lines about "knights, and small, round cows" and "a crack in a rock beneath the boughs." Teddy trusts Jack and Annie to decode these clues, as the SOE is sending him on a separate rescue mission.

Teddy equips them with French identity cards, disguises, and parachute harnesses. He explains they can identify members of the French Resistance, citizens secretly fighting the Nazi occupation, by flashing the V Is for Victory hand sign. He flies them across the English Channel in a small spy plane. In the rush, Jack realizes Teddy forgot to give them the wand and rhyme, but Annie has already jumped. Jack follows immediately.

After landing safely, Jack tells Annie about the forgotten magic. They note a road sign reading "Biéville" near a white church, marking their pickup point. As Nazi search parties close in, they hide in a barn. A German shepherd discovers them, but Annie calms the dog by whispering to it. Gaston, a local Resistance farmer, finds them and returns Annie's V sign, confirming his allegiance. His wife, Suzette, welcomes them into their farmhouse.

In the cellar, Annie discovers Resistance flyers reading "HOPE AND COURAGE! FREEDOM SOON!" Suzette explains that her twin sons, Tom and Theo, printed them as couriers but were captured by the Nazis three months ago. The next morning, the BBC broadcasts the signal that the Allied invasion will begin June 6. Jack realizes this is D-Day. Gaston receives orders to destroy communication lines and infrastructure ahead of the invasion and urges Jack and Annie to leave France before the battle. Suzette identifies the River Orne as the waterway in Kathleen's message, and Gaston notes that limestone caves exist near Mondeville, east of Caen. Neither can decode the references to "knights" and "small, round cows." The couple gives them bicycles, berets, and a compass belonging to their sons.

Riding toward Caen, Jack grows overconfident and flashes the V sign to strangers who turn hostile, flagging down a Nazi motorcyclist. Jack and Annie abandon their bikes, and a milkman hides them in his delivery truck, misdirecting the soldier. In Caen, they board a train for Mondeville, but Nazi officials inspect Jack's pack and find Resistance flyers that Annie secretly took from the cellar, hoping to distribute them as the twins had done. The official begins to arrest Jack, but Resistance fighters blow up the tracks ahead, and Jack and Annie escape through a window.

At Sylvie's Bistro near the River Orne, the owner, Sylvie, reveals herself as a Resistance ally. She tells them Tom and Theo escaped prison and fled to Spain. Speaking in code with Nazi soldiers nearby, Sylvie explains that "Yellow Knights" and "White Calves" are apple varieties, decoding Kathleen's cryptic references. She directs them to a deserted château on the Road of Rocks, where an orchard grows near a rocky hillside. Jack asks Sylvie to send a message so Gaston and Suzette will learn their sons are safe.

At the château, Jack and Annie squeeze through a crack in the hillside into a limestone tunnel. In a candlelit cavern, they find Kathleen, exhausted and thin, with ten small children. Her SOE mission was to retrieve two Jewish sisters, Sophie and Sarah, whose scientist parents were arrested by the Nazis and later escaped to London. At the abandoned orphanage, Sophie and Sarah were caring for eight other Jewish children. Kathleen could not leave any behind and has been hiding them in the cave by day and the château's attic by night. Sadness and terror have drained her magic powers. Jack tells her they must leave by nightfall because bombs will fall the next day.

They devise a plan: Annie sends a message requesting a bigger plane, while Jack finds an unlocked bakery delivery truck whose cab resembles his great-grandfather's farm truck, which Jack learned to drive back home. He drives it to the château and loads the children. At a Nazi checkpoint, Kathleen tells Jack she has remembered an invisibility spell and recites a rhyme. Jack relaxes and drives calmly through. Afterward, Kathleen confesses she lied: She still has no magic. She knew the truck would draw no attention as long as Jack drove confidently. Jack laughs, realizing he succeeded on his own.

They settle the children in the white church at Biéville. When they return outside, a large silver plane sits silently in the dark field. Teddy emerges, explaining he called upon a friend for help. The plane lifts off with no noise, undetected by searchlights. Annie releases the Resistance flyers from a window, and Kathleen, joyful and reunited with Teddy, speaks an enchantment that multiplies them into tens of thousands. Her magic has returned, restored by hope and the knowledge that the children are safe.

The plane lands near Glastonbury Tor. As Sophie and Sarah approach a waiting motorcar, their parents climb out and embrace them. Kathleen promises to protect all the children until they find safe homes. Teddy leads Jack and Annie to the abbey ruins, where Merlin reveals he conjured the plane, a magical creation that could land undetected. He tells them they experienced firsthand what it means to live in constant terror and thanks them for overcoming their fears. Back in the tree house, they see D-Day planes heading toward Normandy before wishing themselves home. Walking through the Frog Creek woods, they reflect on the courage of Gaston, Suzette, Sylvie, and the milkman, who risked their lives to do the right thing. Jack appreciates his ordinary freedoms anew, and they enter their house, grateful for their safe, free lives.