Past a windmill, and past a bridge, there is a spooky-looking house where a Cubone enters the front door. The doors slam behind Cubone as it looks on at the empty house. Koffing, Shuppet, Misdreavus, Duskull, Gastly, and Sableye peer through holes in the ceiling as Cubone explores the house. Koffing uses Smog down the chimney, as a Golbat flies outside of the fireplace to scare Cubone and send him tumbling backwards. Haunter's hand creeps closer to Cubone as it uses Bone Club to try to scare the ghost away. Cubone hits Haunter's hand and it hits Haunter in the head as it's confused as to what just happened.
As Cubone walks down the hallway, a Lickitung uses Lick on its face. Cubone is scared and pulls on Lickitung's tongue so that it comes down hard to the ground. Cubone finds a mirror and looks at its own reflection, but a Ditto using Transform moves differently. Cubone hits Ditto with the bone, and Ditto is knocked out as it transforms back into Ditto with a bump on its head. Banette, Dusclops, and the other Ghost-type Pokémon come to check on Ditto to make sure it is okay. Everyone feels bad about what happened to Ditto.
Pikachu with a picnic basket, Corphish, Munchlax, Phanpy also with a picnic basket, Mudkip, and Squirtle are going up a hill, as Squirtle is so tired that he falls over and starts whining that it is too tired to keep going. Pikachu carries Squirtle the rest of the way, as Munchlax also drops down from exhaustion. Munchlax complains that it is very hungry, and the Pokémon decide to take a break and eat the picnic food. A Bonsly eats a berry from a tree, notices the other Pokémon eating, falls out of the tree, and uses Fake Tears claiming it is hurt and hungry. The Pokémon offer to give Bonsly the food, and the Bonsly begins to eat. Golbat had been watching the Pokémon the whole time, and goes back into the house to inform the Pokémon that live there. They make a plan on how to lure the other Pokémon and to scare them inside of the house.
The Pokémon open the windows to the house, and start to perform Rain Dance outside of the windows. It begins to rain outside, and Pikachu and his friends head to the haunted house to get away from the rain. Pikachu knocks on the door, but there's no answer. Corphish tries to use Tackle to open the door, but the doors end up opening on their own as Corphish heads inside and runs straight into the fireplace. The other Pokémon head inside and are a bit scared. Koffing uses Smog down the chimney to scare the Pokémon into running back out of the door, but the door shuts before they can leave. While inside of a ghost sheet, Duskull and Dusclops use Will-O-Wisp and approach the Pokémon to scare them. The camera shows the Pokémon hidden in the sheets as if the sheets were see-through. The Pokémon back up, go invisible, which scares all of the Pokémon into screaming.
They run up the stairs, as Lickitung uses Lick to send them backwards. Haunter's hands crawl up to them and dance as the Pokémon look on in fear. Golbat shows up with Sableye on its back, flies around the Pokémon while still scaring them. Squirtle begins to cry very loudly, as Golbat and Sableye hit the ground in shame. The other Pokémon who were pulling pranks, along with Gengar, feel ashamed as well. Gengar tries to make Squirtle laugh by showing it a picture of a smiley face with a tongue sticking out on its stomach. Squirtle keeps on crying. All of the Pokémon involved with scaring them come to try to cheer up Squirtle, but Bonsly starts to use Fake Tears which hurts everyone's ears. Pikachu and Haunter try some new funny faces, which finally get Squirtle and Bonsly to stop crying. They start laughing, and then everyone joins in on the laughter.
The Pokémon gather some fruit in another room and place them on tables. The Pokémon who were scaring everyone, apologize for scaring them, and explain that they were only doing it for fun. All of the Pokémon eat the fruit as colorful bubbles float around. Munchlax tries to swallow a whole watermelon, but chokes and has to spit it out as the other Pokémon laugh. Sableye cuts the watermelon into slices so that each of the Pokémon can eat it. The Pokémon hear the gate doors crashing to the ground and go check to see what is going on. Team Rocket and Wobbuffet have a crane with Cacnea attached to it and are preparing to wreck the house. Golbat flies back inside to tell the Pokémon what is going on. The Pokémon decide that they will do what it takes to stop the machine. Meowth has Wobbuffet move the crane to break some of the wall off the house with Cacnea's help.
Ditto transforms into Wobbuffet, and forms a protective barrier around the house so that the crane can no longer wreck it. The impact with the barrier sends the crane backwards as it crashes to the ground, with Meowth and Wobbuffet crawling out. The other Pokémon are happy to see the crane no longer usable. It begins to rain outside, and Meowth and Wobbuffet enter the front doors to the house. The front doors close behind them on their own, and startle them. Koffing uses Smog down the chimney. The Pokémon again hide in a ghost sheet, use Will-O'-Wisp, and go to Meowth, Cacnea, and Wobbuffet to frighten them. This time the Pokémon make an angry face to scare them even more. The Pokémon back away and disappear as Meowth, Cacnea, and Wobbuffet shake in fear. Mudkip, Cubone, Pikachu, and Misdreavus watch it all happen. Will-O'Wisp is sent towards Meowth and his friends, and Haunter's hands crawl and dance to them, making them scream really loud in fear. They run up the stairs and down the hallway before Lickitung uses Lick to send them backwards to the ground.
They crawl the rest of the way down the hall, to a room filled with knights and end up in front of a moving one. Gastly moves the knight's face armor to reveal itself, and the Pokémon scream even louder while running further down the hall. Wobbuffet and Cacnea end up in armored suits, run into each other, and fall backwards. Banette and Shuppet jump out of the armor with Gastly and laugh. Meowth goes further down the hallway and is met by the shadows and glowing white eyes of Misdreavus and Sableye and runs away. The two Ghost Pokémon laugh about it. After entering through different doors to the same room, Meowth and his friends run up some more stairs. Cubone pulls on a rope that turns some wheels and flatten the stairwell which causes the Pokémon to slip and fall down the stairs. They hit a revolving door and keep going in and out of it while getting dizzy. Meowth crawls through the crawl space and exits through a small metal door. Meowth looks at his reflection in the mirror, but the reflection does follow what he does which scares him. The reflection pulls down their eyelid at him and Meowth runs away. The reflection turns back into a Ditto as it laughs. Bonsly, Munchlax, Squirtle, and Mudkip decide to pull off a scare as well, as Meowth enters another room with the door closing behind him. They approach him with a ghost sheet over their heads which terrifies Meowth at first. Meowth starts to suspect that it's not a ghost, and then the ghost falls over while revealing who's really behind that scare.
Meowth yells at the Pokémon for scaring them, Wobbuffet and Cacnea are angry, and Pikachu with his friends are watching from the ceiling. Several of the Pokémon pull up and down a lever to send something water into a balloon covered in a sheet towards Meowth and his friends. Pikachu calls out to the other Pokémon to exit through the door since the others are distracted. Meowth pulls the sheet off to reveal a Pikachu balloon that keeps on expanding. Mudkip and Squirtle use Water Gun to power up a second balloon. Meowth and the others try to run away from it in fear but the balloon keeps on following them, while another appears as well. They try to get them to hit each other, but they still turn and chase them. After going into another room, the Pokémon try to hold the door shut so the balloons can't get through. The balloons keep expanding and are able to break through the doors to keep chasing them til they are stuck against the wall. Cacnea uses Pin Missile to break the balloons. The balloons burst out water which sends Meowth, Cacnea, and Wobbuffet through the roof and blasting off into the sky.
The Pokémon all gather around and enjoy the campfire, and then fireworks are set off into the sky as everyone enjoys them. Pikachu smiles as he watches the fireworks.