I will try not to make this too long........
It will start off where the first movie had ended, when Stine finds out that The Invisible Boy is still out of his manuscript. Stine manages to run away and escape from The Inivisble Boy and goes to warn the kids of what happened. Zach then tells Stine to quickly write a new manuscript so they that will be able to capture the loose monster. Stine tellls the kids that he left the typewriter in the classroom. So they head back to retrieve the typewriter, but find out that it's missing. They head back to Stine's house to devise a plan. Once they get there, they find The Invisible Boy in Stine's Study. The Invisible Boy tells them that he's in charge of the town and he plans on giving it a "makeover", then he opens the "One Day at Horrorland" manuscript. Pretty soon, the whole world is being taken over by Horrorland. Stine and the kids, start to hunt down The Invisible Boy in the haunted theme park. Meanwhile in the Goosebumps Universe, Slappy senses the appending danger because Horrorland is a both a threat to The Human World and The Monster World. The Invisble Boy soon manages to contact him through hologram and tells him that he is the new leader of The Monsters and The Humans. Slappy then gets angry and tells The Invisible Boy that he was always jealous of his leadership from the beginning. The Invisible Boy then tells Slappy that he would do anything to kill him and hangs up. Slappy then decides to head back to the real world to help Stine and the kids.
Back in Horrorland. The Invisble Boy announces that he is in charge and that he loves the town's "new look". Slappy and the other monsters finally head out of the manuscript and warn the people of Madison that they are in grave danger and they have to leave. The town doesn't believe them and thinks that it's just another Monster Invasion. Stine is shocked of what Slappy was trying to say that he actually believes him. Stine then steps up to the podium and tells them that if The Monsters and The Humans teamed up, they will be able to stop Horrorland. So The Monsters and The Humans team up in seperate groups. Stine is teamed up with Slappy, Zach, Hannah, Champ, The Werewolf of Fever Swamp and The Praying Mantis. They soon leave and head out into Horrorland. Meanwhile, The Invisible Boy overhears their plan and starts his own Monster Army. He then contacts a hooded figure to kill Stine and the gang.
Later on, Stine, the kids, Slappy, The Werewolf and The Praying Mantis are walking to a dark, dense forest, Stine then asks why Slappy had wanted to kill him 6 months prior. Slappy tells him that once Stine had created the other monsters, including Hannah, he felt left out. So he started a Monster Army to kill him, to prove to him that he's just as powerful. Stine then apologizes to the ventriloquist dummy and promises that during this mission, he will never feel left out. Soon, they hear a rustle in the bushes. They try to figure out where it's coming from, until the hooded figure that The Invisible Boy was talking to attacks them from behind. The gang tries to fight back, then the figure reveals himself. He has red hair, a red and green flannel shirt, blue jeans and black and white sneakers. He introduces himself and tells them that his name is Wally Wood. He also tells them that he doesn't want to hurt them and that he was forced to by The Invisible Boy. Slappy is happy that he is reunited with his little brother that he lets him join them on their mission. As they continue their journey, Wally tells them how he was left in Chicago and was homeless. He tried to sell inventions to make money, but they had always backfired on him. He also said that he lives in an abandoned R.V. which he had fixed up and drives it wherever he goes. Champ says that it will be useful for the mission because Wally had installed a GPS in the R.V. so they will be able to get around Horrorland. Later that night, they find a place to camp out. The kids start to worry what would happen if they don't stop Horrorland and The Invisible Boy. Slappy deciding to be nice for once, goes over and calms them down and tells them that everything is going to be fine, as long as everything goes as planned.
The next morning, the gang wakes up and finds out their camping spot had been trashed. They soon look over and sees Cuddles the Hamster eating all of their food and wrecking Wally's R.V. Literally, Wally has a freak attack and starts to attack the giant hamster. This angers Cuddles and he sends, Ray Thurston, The Blue Kerlew Hound, R.I.P. the Cat, and The Barking Ghosts to go fight Stine and the others. During the fight, Slappy gets a text message from The Invisible Boy asking if Slappy loved playing with his "new friends". Slappy yells at the top of his lungs that he doesn't like them and sucker punches Ray. The Werewolf and The Praying Mantis manage to fight off R.I.P the Cat and Cuddles, while Stine, Wally and the kids fight of R.I.P., The Blue Kerlew Hound and The Barking Ghosts. After the fight, they continue the journey. The manage to catch up with Aunt Lorriane, Zach's Mom, The Abomindable Snowman, Count Nightwing and The Haunted Mask. They talk for a little while until The Abomindable Snowman starts to act strange. It turns out that he is being mind-controlled by The Invisible Boy to attack the two groups. The others try to knock some sense into him, but it's too late because The Snowmant was about to punch Stine. Slappy then jumped in front of Stine just in time and takes the punch instead. Slappy is then knocked unconscious, and starts to clutch his head in pain. Finally free from his trance, The Snowman feels bad for what he done to his friend. Stine tells him that it wasn't his fault and was forced to attack without knowing. Wally then tells him that they better find a cure for Slappy and quick because ventriloquist dummies have very sensitive skulls and he could die. But Stine wants to finish The Invisible Boy once and for all. So they put Slappy somewhere safe and they go and fight The Invisible Boy.
The finally find The Invisible Boy and start to confront him. They even blame him for Slappy getting badly hurt. The Invisble Boy replies by saying that Slappy deserved what he got and they might as well get used to not having him around. This angers Stine that he starts to beat up The Invisible Boy, while the others fight his henchmen. Wally soon finds out from Hannah that the reason why his inventions never worked was because he actually built weapons instead. So Wally starts to use them in battle. Stine finally chases The Invisible Boy up a cliff and corners him. He tells him to never hurt his family again and he pushes The Invisible Boy off the cliff and into The Doom Slide where there is a black hole and it sucks him up, never to be seen again.
After the fight, Stine and the others head off to check on Slappy. They find out by Aunt Lorriane had stayed behind and looked after him that he passed away as they were fighting The Invisible Boy. Stine then cradles Slappy in his arms and tells him that he was always his family and that he would never leave his side again as he starts to cry. Pretty soon, a tear lands on Slappy which in turn, brings him back to life. Slappy then finds the "One day at Horrorland" manuscript and sucks the theme park back into the book.
6 months soon pass and The Monsters and The Humans are helping to fix the town. Stine then announces that a couple of monsters are willing to stay behind in case something like this happens again. The monsters include, Slappy, Count Nightwing, The Haunted Mask, The Werewolf, The Praying Mantis and The Abomindable Snowman. Wally then prepares to head back to Chicago, but Slappy stops him and tells Wally that he is part of their family and the team wouldn't be the same without him. Wally accepts the offer and decides to stay with them. Then, Stine and the others go into Wally's new and improved R.V. and they drive off into the sunset to fight off more dangerous monsters.
What do you guys think???????? -Slappy'sGirlfriend2598.