A family moves into a old mansion and finds it is surrounded by magical creatures. Freddie Highmore plays the lead character Jared Grace. He also plays his identical twin brother Simon wearing slightly different clothes, hairstyle, and makeup. He has a sister named Mallory (played by Sarah Bolger). His mom Helen Grace (played by Mary-Louise Parker) makes them move to their Aunt's mansion because they have nowhere else to stay since she is getting a divorce. Aunt Lucinda Spiderwick (played by Joan Plowright) was put in a mental hospital so the mansion is empty when they arrive. Jared wants to live with his father. His father is supposed to come the next day, but calls on the phone to make an excuse for not coming. Jared's mother does not want to tell him that his father found another woman and does not want Jared to live with him anymore. Jared is always playing pranks on his sister, acting out, and getting into trouble. When Jared hears something in the walls of the house, nobody believes him. He punches a hole in the wall and finds an old dumbwaiter. He gets inside it and pulls himself up to a hidden room, which is a science lab. He searches the room. He finds a book in a trunk that is sealed with ribbons and wax, The book has a note on it warning not to read it. The note says that anyone reading the book with bring themselves and their family into grave danger. Something is in the room with him, but he is not able to see it. He opens the book anyway. The house shutters when he opens it. He begins to read the details of the life-long study by Professor Spiderwick, where the professor discovered the world of fairies, goblins, and other mythical creatures, which he writes about in detail. He also reads the warning about the Mulgarath (played by Nick Nolte) that is the most evil of all. He spends the night in his bedroom inside a big trunk, reading the book. In the early morning hours, there is a scream. His sister has her hair tied to the bedposts so she is not able to move. Jared's mother and his sister think it is prank done by Jared, but Simon confirms Jared was in the trunk all night.
Jared reads about one creature that can be very mean-spirited unless it gets some honey, and then it becomes very docile and friendly. He leaves honey on crackers in the science lab to try to make it come out. One of the crackers is eaten. He tracks down the crumbs. A little tiny creature appears to him delighted with the honey. Jared gives it more honey. Its name is Thimbletack (with the voice of Martin Short). Thimbletack asks Jared if he read the book. Jared says yes. Thimbletack becomes very worried and says the book may never leave the safety of the circle around the house. In fact, none of them can safely leave now because the house is surrounded by hobgoblins ever since Jared opened the book. He gives him a special stone to look through so he will be able to see them, as they are otherwise invisible. Jared sees many goblins just outside a ring of mushrooms growing around the house. He also sees Simon about to cross the circle toward the goblins. He calls to Simon, but it is too late. Simon is caught by them and dragged away into the deep forest. Jared goes after them. Jared finds Hogsqueal (with the voice of Seth Rogen) held in a cage. Hogsqueal begs him to free him and he will aide in the fight against Mulgarath. Hogsqueal spits on Jared's face giving him the ability to see the goblins all the time without using the stone. Jared frees both Hogsqueal and Simon. They all run back towards the house. Mallory is coming towards them. She crosses the line of the circle. When one goblin bites Simon, she sees the tooth marks, which convinces her they are real. They convince her to fight the goblins now attacking her legs. She fights them off with a sword she uses to practice the sport of fencing. They all get back to the safety of being inside the circle of protection.
They decide the best way to figure out what to do is to visit Aunt Lucinda in the mental hospital. They discover a map to a series of tunnels that leads underground all the way to the town. Jared and Mallory go because Simon is injured. They reach the hospital, find Lucinda, and tell her Jared read the book. Lucinda tells the fairy creatures in the flowerbeds to come out of hiding. She warns them they are in grave danger. Jared shows her the book. She is terrified that it is outside the circle of protection. She tells them they must find her father Professor Spiderwick and get him to destroy the book. She says the fairies have told her he is still alive even though he has been missing for over one hundred years. The room is attacked. The goblins break through the window. They do not get the entire book but they manage to steal some of the pages from it. Lucinda throws salt on them, which burns them. Jared's mom shows up, can't see any of the invisible creatures. She takes Jared and Mallory home with her. She tells them they are making up all this nonsense about creatures just to get out of staying in the old house. Jared becomes mad at her because she does not believe him. He tells her he does not want to live with her anymore.
Jared figures out the way to see Professor Spiderwick is to call his pet griffin and the griffin will take them to where the professor is being held. Hogsqueal spits in the faces of Simon and Mallory also giving them the permanent sight of the creatures. They call the griffin and it flies them to see the professor. The professor wakes from a trance. He thinks he has been gone only a few hours, not over a hundred years. Jared tells him what is happening and asks him how to destroy the book. He tells him there is no way to destroy it; instead, Jared must destroy the Mulgarath. He insists they fly back on the griffin right away, before they fall under the spell and are trapped with him. The professor distracts the fairies with a fake book and they escape. They fly home on the griffin. They run back to the house barely ahead of the goblins chasing them. They see their mother driving up and jump in her car to get back inside the circle. The mother thinks they are crazy until she looks through the stone and sees all the goblins are real.
Mulgarath reads the pages of the book, which they stole. They tell him that on the full moon, which is the next night, the protection circle spell can be broken so they will be able to attack the house. The family prepares for the attack with tomato juice and salt that can be used against the creatures. The next night the circle of protection is broken. They have in intense fight with the creatures. Mulgarath chases Jared to the upper floors as an ogre, and then he changes into a snake to climb up the dumbwaiter shaft, then out on the roof he changes back to an ogre as he corners Jared at the very top of the highest point on the roof of the mansion. Jared makes him fall off the roof. Rather than be harmed by the fall, Mulgarath changes into a bird. He flies near Hogsqueal who grabs the bird as it passes and eats it, since birds are his favorite food. Mulgarath is destroyed. The family is brought together from this and Jared apologizes to his mom, telling her he wants to live with her.
They bring Aunt Lucinda back from the mental hospital to the mansion. Professor Spiderwick arrives surrounded by a cloud of fairies, which are so happy that Mulgarath has been destroyed. Sadly, the professor is not able to stay, for if he did he would instantly change to dust from his real age and die. Lucinda is so happy to see her father once again and asks this time may she go with him. He says of course and Lucinda changes from an eighty six year-old woman into a young girl. Lucinda and her fatherm Professor Spiderwick, go off with the fairies to fairyland to live happily ever after.
Best part of story, including ending:
I like stories about creepy old mansions with spooky things and hidden mysteries, which lead to an adventure.
Best scene in story:
I like the scene when they discover Professor Spiderwick in the fairy garden and the way Jared avoids the fairy enchantment by listening to loud music in his headphones. It a great reason for him to play the music loud and I like loud music.
Opinion about the main character:
I especially liked the performance of the actor Freddie Highmore, because he was able to play two identical twins, who look slightly different, just enough to make them seem like two different persons. I thought he did an excellent job and was convinced there were two twin actors until I read the credits.