Haunted Castle on Hallow's Eve is second book in the Merlin Missions series. It was originally published as the 30th book of the combined Magic Tree House series.
This is the first book where Jack and Annie have proven capable under the right circumstances of performing their own magic.
Synopsis[]
In their magic tree house, Jack and Annie are again transported to King Arthur's realm, where invisible beings, giant ravens, and mistaken magic spells have a duke's castle in an uproar on Halloween night.
Chapters[]
- All Hallows Eve
- The Heart of the Oak
- Rok
- The Castle
- Ghosts!
- Merlin's Diamond
- One, Two, Three
- SPREE! SPREE!
- A Piece of a Star
- Where Is It?
- Or Else!
- A New Day
- Jack and Annie's Magic
Plot[]

The leaf that took Jack and Annie near the duke's castle.
It was Autumn, Jack and Annie were talking about their Halloween costumes. Suddenly, a raven landed near them and flew off again. Seeing this as a sign from Morgan, the two returned to the tree house and found a yellow leaf that told them to look for “M” in the tallest oak on All Hallows Eve’. Remembering Christmas, Jack and Annie realized that the “M” who sent this was Merlin.
The leaf invitation took them to a thick forest and they were wearing Camelot costumes. In the tree the tree house was on, there was a crack that led to a hidden room. Inside was Merlin, since Jack and Annie were Master Librarians and Magicians of Everyday Magic, Morgan believed they could help Camelot again. In another room was a guide for them, it was Teddy! Merlin was actually surprised they knew him, the kids told him their adventures when he was a dog, he was fascinated by their friendship saying it will help with their mission. They were in one of the outlying realms of the Camelot, beyond the woods is a duke’s castle, they must bring order to it. He also warned Teddy to use his magic words wisely, which he agreed to do so.
On their way to the castle, Teddy revealed that his father was a sorcerer and his mother was an Otherworld wood sprite. They came across a village, but some children living there told them that the castle had been terrifying ever since the ravens arrived. Old Maggie, who used to work there, got scared by ghosts two weeks prior. The villagers got scared when a raven arrived, but Annie wanted to be nice to it. As they went inside, Teddy revealed that he studied Dove language at the Isle of Birds. Annie, who also had a skill with animals, named the raven Rok, because that’s what he said. Rok managed to fly again despite his injury, Teddy believed her words healed him. Suddenly, Old Maggie came out and said the following before going back in:
Where is the girl
who spins wool into thread?
Where are the boys
who play chess before bed?
Where is the hound
who waits to be fed?
The castle itself didn’t seem very protected, Annie and Teddy were fine with this, but it made Jack suspicious. Teddy tried to use a rhyme to unlock the doors, but they weren’t locked. The castle seemed empty and Jack wondered about a tunnel of fear Merlin had mentioned. They decided to go to the tower where the family lived, they didn’t see anything out of place as they went. At last, they found a mess in the great hall to clean up, but just as they finished, they saw one of the leftover bones floating in thin air! They were so horrified, they ran up stairs and found a nursery, but inside a spinning wheel was spinning thread all by itself and chess pieces were sliding on a board. However, Annie realized that these things matched Old Maggie’s words entirely. That meant they were just invisible kids and a dog, Annie decided to just talk to them. The girl at the spinning wheel stopped and wrote “Diamond of Destiny stolen” on a mirror. Teddy realized that the castle guards Merlin’s magic diamond, the jewel in King Arthur’s sword of the stone! It is said that the diamond will give the same power to the next ruler of Camelot. Merlin secretly gave it to a family for protection and gave them good fortune in return, but they’d fade from life if they failed to protect it. It’s usually kept in a small space behind a tapestry, but the ghost girl said it was stolen by the Raven King. Teddy was horrified, but he understood. He explained to Jack and Annie that the Raven King is a terrifying creature from the Otherworld, he read that in a book from Morgan’s library. The Raven King was born a human boy who wanted to be a bird, he stole a spell from the Wizard of Winter but didn’t have the proper magic, so it only worked halfway, making him half bird and half human. Now he commands an army of raven that treat him as their king.
The girl revealed that the Raven King’s hideout was a nest on a craggy mountaintop in the distance. Teddy secretly had an enchanted hazel twig from his mother’s cousin, he decided to turn himself into a raven and go get it back. However, he accidentally turned Jack and Annie into birds as well, nonetheless, they all managed to fly. They managed to reach the nest, there were two ravens by the entrance as guards. Teddy decided to distract them while Annie kept watch and Jack got the diamond. Although Jack was briefly scared, the plan was successful, except Teddy didn’t come back. A bunch of ravens were coming, but luckily, Jack and Annie saw Teddy’s lantern in the castle. They say some magic words to turn themselves back to normal, but Jack apparently dropped the diamond. To make matters worse, the Raven King arrived, revealing that he had caught Teddy! Suddenly, Rok, one of his bodyguards, arrived with the twig. Not wanting to hurt anyone, Jack decided to turn the Raven King into an actual raven. Once all the ravens left, Annie turned Teddy back to normal. The ghost girl hid the diamond from the Raven King, once the diamond was returned to its rightful place, all the ghosts took shape. They were Gwendolyn, Tom, and Henry, and the dog’s name was Oliver. Gwendolyn explained that everyone else was sleeping when the Raven King stole the diamond. They often snuck out of bed and they stumbled upon the secret room. Gwendolyn wanted to get a better look at the diamond so she put it by the window to catch the moonlight, but when they did their activities, the Raven King took it and they faded before they could tell their parents. Since they were sleeping, they won’t know about this, the kids thanked Jack, Annie and Teddy and went off to wake their parents.
As the morning arrived, the village was much more lively. Merlin was pleased that their mission was a success, he returned to Morgan having Teddy carry books for his studies. When Jack and Annie came back to Frog Creek, they found that nothing seemed spooky to them. They decided to stay home and help their parents give out treats this Halloween.
Publication Note[]
This book was originally published as book #30 of the Magic Tree House Series. In 2017 the books where Merlin sets the mission were separated from the main series and given their own numbering system.
Trivia[]
- At the beginning, a passage from an old Irish ballad, Earl Desmond and the Banshee, is shown. The hearth is cold in the lonely hall, No banquet decks the board; No page stands ready at the call, To tend his wearied lord. This is when the titular character returns to find a quiet room due to people mourning his wife.
- Jack defeating the Raven King served as a preview for him and Annie learning real magic later on.