As the sun shines down on the city, Pikachu, Happiny, and Piplup are on top of tires getting ready to go down the slide. Togekiss flies around with Pachirisu on its back. Staraptor is sleeping on another set of tires. Mamoswine and Torterra are standing around. Buizel, Sudowoodo, Infernape, and Gible play on the teeter-totter. Buneary and Cyndaquil swing on the swings. Pachirisu slides down the slide, on Mamoswine's tusk, and into Torterra's tree on its back. Pikachu and Piplup do the same except they slide across Torterra's side and into some tires. Happiny slides down and lands in Torterra's tree. As Piplup is inside one of the tires, Pikachu runs on top of the tire sending them down the alleyway. They run into a fence and fall to the ground.
Pikachu and Piplup look into the sky and see something shine and an Unown shaped as the letter F falls out of the sky and into the tire. When Unown lands in the tire, it sends Pikachu and Piplup flying and hits the ground hard. Unown comes out of the tire and looks like it doesn't know where it's at. It tells Pikachu and Piplup where it came from, but they don't understand. Wobbuffet, Mime Jr., and Team Rocket watch from behind a fence to see what is going on. Skitty arrives at the alleyway and asks the Pokémon what is going on. Unown tries to explain where it came from, but Pikachu and Piplup don't understand what it's talking about. Skitty understands what Unown is talking about and shows them where to go. As they walk down the alleyway, Meowth, Mime Jr, and Wobbuffet come out of a trash can and watch where the others are heading. Meowth imagines with them getting a lot of money for the Unown and seeing the Unown Dimension. They chase after the other Pokémon while in a hidden spot, Croagunk notices what is going on. Skitty leads the Pokémon through a sewer, and to a wall that has shapes of a triangle, square, and circle on it. Skitty pushes the triangle button in, as a line connects to the circle which pushes out and hurts Piplup, sending him backward. Pikachu pushes the square button as a line connects to the circle which pushes out. Meowth and his friends arrive and want to join them, but Piplup doesn't trust them. Meowth comes up with a plan to catch the Unown, and tries to grab it but instead pushes in the square button which connects the final line to the triangle shape and opens up a portal.
The portal brings all of the Pokémon into the Unown Dimension. Croagunk and a Marill were brought into the dimension as well. The wall closes behind them as the triangle pushes back out. They are sent through a shiny and sparkly portal that has colors of yellow, blue, green, pink, purple, and white with streams of lines running across. As they exit the portal, they fall out of a blue sky and land on stone blocks shaped like a puzzle. Piplup decides to jump across the stones and almost falls off. Pikachu and Skitty also jump across the stones. Piplup jumps into too far of a gap and falls through the hole between a couple of stones. Piplup lands back where he started when they entered the Unown Dimension, as he breathes a sigh of relief. Piplup and the others continue across the stones, as right behind them Meowth and his friends start jumping across the stones as well. A Marill steps in front of them and uses Sing to put them to sleep. After it is done singing, Marill inflates and hits the group with its tail and sends them off the stones.
They land on more stone blocks, but this time they are together and the whole area looks exactly like a desert and is made of all stones and stone walls. Pikachu and his friends also end up there and notice that Meowth and the others are following them. Meowth chases after them. All of the Pokémon enter a stone cave and go through a bright light at the end of it. They enter through the same looking portal as they did before. They go through more of the portal which is green, yellow, red, purple, blue, and black while it looks like a multicolored space swirly in circles. They enter another area which has multicolored background, and a silver-colored-looking tornado. While passing through, Meowth and his friends look like they are flat and are moving around the place.
Pikachu and his friends land again in a desert-like place but with green plants around. They look up and see a giant Meowth, Wobbuffet, and Mime Jr. They realize they are much bigger and start chasing after the other Pokémon. Mime Jr. jumps and almost lands right on top of them. Meowth steps in front of them and tries to flatten them with his hand. Meowth and his friends keep chasing after the other Pokémon and end up going through the portal again. This time Pikachu, Piplup, Skitty, and Unown are also shown as flat and moving around the place. Meowth and his friends land on Pikachu, who is now large-sized. They tell Pikachu to let them down, but Pikachu moves his head back and forth to move them around. Pikachu shocks them with static electricity. Meowth tells Mime Jr. to use Teeter Dance to make everyone dance along. The dancing makes the ground shake around them. After spinning around, Meowth and his friends are sent blasting off high into the air. On the other side of the dimension, Croagunk is shown with a disgusted look on his face as he sits on a tall stone rock. They land hard on the ground and in front of the singing Marill. They try to make a run for it, but Marill puts them to sleep by singing. Marill inflates and flattens them with its tail and the wind sends them blasting off into the air.
Pikachu and the others land in a green field with trees and colorful flowers. They meet Uxie, Azelf, and Mesprit who bring them to some apple trees. They hand Pikachu, Skitty, and Piplup the apples to eat. The Pokémon thank them and start eating the apples. When Meowth and his friends land, they are surrounded by Oran Berries. Meowth grabs what he thinks is an Oran Berry, but it's actually Marill's tail. Marill uses Sing to put them to sleep. After Marill stops singing, it inflates and slaps them with its tail. In another area of the field, Croagunk finds another fruit but doesn't like the taste of it and is disgusted by it.
Pikachu and his friends land inside a cave-like doorway that leads to a sky full of large stone blocks. In the middle, there is a tall stone tower that appears to go up into the funnel-shaped clouds. The sky is blue, pink, and purple surrounding the stone blocks. The Pokémon climb up the stone stairs but Piplup falls and takes Pikachu and Skitty down with him. A Deoxys grabs them and brings them to the top of the portal. Once they reach the top, Deoxys places them on a colorful-looking and sparkly ground. In the sky, a lot of Unown of different letters floating around with clear colored funnels shaped like tornadoes. A couple of Unown come down to see their friend and are glad to see each other as they dance in a circle. The Unown thank Pikachu and his friends for their help. The Unown use their powers to bring the Pokémon to have fun, play, and dance with the other Unown. Meowth and his friends show up and see the huge groups of Unown as Croagunk watches them. Pikachu and the other Pokémon see their friends through a funnel-shaped opening in the dimension and say to Unown that they need to go back to their friends.
Pikachu, Meowth, all of their friends, and Marill jump back into the same portal they came through before. Pikachu and his friends land on top of the tire fort. They are relieved to be back and done with their adventure. The Pokémon all watch the fireworks together. Meowth and his friends also were watching the fireworks together. The singing Marill arrives behind Meowth. The episode ends with Pikachu and Piplup watching the fireworks together.