Ash and friends are now heading for Slateport City, home of the Hoenn Grand Festival! Along their way, they’ve stopped on a little tropical island in the southern seas of Hoenn. In the middle of the forest, they spot tons of Berries on trees everywhere. They spot Cheri Berries, Pecha Berries, and Pikachu happily munches on an Oran Berry. Ash grabs a red Tamato Berry and, despite Brock’s warning, chomps down on it. His mouth suddenly feels like its on fire and he starts screaming and running around.

At the Pokémon Center, Nurse Joy thinks he’s a monster until he tells her that he's “Bash Betchum from Ballet Bowd!” Brock begins to flirt with Nurse Joy, but Max pulls his ear again. Everyone gives Nurse Joy all of their Pokémon, except Ash who takes Snorunt out to work on its “Ice Beeb!” Pikachu follows but gets hit in the face with the automatic sliding glass doors. Some kids walk by talking to each other about making some Pokéblock from Liechi and Pecha Berries. May asks Nurse Joy if they have Berry Blenders, and Nurse Joy tells them that they do and that May can use them any time with any Berry on the island.

Meanwhile, Team Rocket is working as gardeners for the Pokémon Center. In the courtyard, they lay down on the ground to look at the clouds and find their stomachs being stepped on. Looking up, they spot a Munchlax nearby. It starts to walk away without a care in the world. Jessie, James, and Meowth start to give chase but stop when they spot a Berry Blender through the window.

Ash has set up a target for Snorunt to aim its Ice Beam at. The first attempt almost makes it, but the beam swerves upward and soars into the sky. Ash shakes his head as the beam comes back down and hits him. The ice freezes him, and then breaks. Pikachu and Snorunt giggle as Ash realizes that his lips are back to normal.

Inside the Pokémon Center, Max and Brock watch as the trainers from before place their Berries carefully into the Berry Blender and blend them to make Pokéblock. Brock says that he’ll try his hand at making Pokéblock with the book Natalie gave him at the Flower Shop, before flirting with Nurse Joy again. May walks in with a basket full of all kinds of Berries and says that she’s going to make a new recipe: “May’s Purple Surprise.” Heading for the Berry Blender, May cuts up the Berries to the correct proportion and places them into the Blender. Turning it on, May awaits the results. A couple minutes later, out pop several purple Pokéblocks. Each Brock and Max try one; Brock says that it is definitely a new flavor while Max adds that he wouldn’t even call it a flavor. Outside, Ash gets frozen with Ice Beam again as Munchlax walks past. Ash follows it to the Pokémon Center where May has produced a whole plate of Pokéblock.

The gang’s Pokémon gather around it, eager to try. As each of them tries it in turn, they faint immediately, all except for Corphish. It seems to like it, as pointed out by Max, until it tips over sideways. Munchlax walks up, however, and starts gulping down the Pokéblock like it hadn’t eaten in days. Just then, two “Professional Pokéblock Tasters” walk in, but they are really Jessie and James in disguise.

They say that they’ll taste all the Pokéblock and tell the trainers how it is. Meanwhile, Meowth and Wobbuffet sneak into the Berry Blending Room and steal all of the remaining Pokéblock from the counters. Several trainers give their Pokéblocks to Jessie and James to try. The duo compliments each block without making any useful comments, but the trainers all seem to like the comments made. May approaches and asks them to try her Pokéblock. James doesn’t like it at all and shoots it down, but Jessie loves it and gives compliments galore. Just then, one of the kids notices that all of the Pokéblock are gone. The kids all blame Munchlax for the crime while Jessie and James snigger from behind the counter.

May and Nurse Joy defend Munchlax while Jessie and James also blame Munchlax and May, too. While everyone argues, Munchlax decides to walk off.

Everyone follows it outside, to find it eating an Oran Berry. May proclaims that she’ll catch the hungry little Pokémon to stop all the chaos, and so she sends out Combusken. Munchlax is now at the top of a tree, pulling down a Cheri Berry to eat. May calls the Pokémon down and offers it one of her “Purple Surprise” Blocks. It happily eats the block, standing in front of a tree while eating it. Combusken uses Fire Spin and ends up scorching the tree as Munchlax is gone again. May spins around to see Munchlax holding out its hands for more “Purple Surprise!” She wheels it around and places it in front of the scorched tree, telling Combusken to use Sky Uppercut on it. Munchlax ducks and Combusken hits the tree. May cries out in despair to see Munchlax sleeping on the ground. She wakes it up and gives it another Pokéblock.

With Munchlax ready to battle, Combusken uses another Sky Uppercut… and hits the tree again. Munchlax again has gone to eat a Berry. Inside the Pokémon Center, Jessie, James, and Meowth pack up their Pokéblocks and get ready to move out. Before they do, James picks up a Tamato Berry and screams out in pain. He runs through the Center wall and out to the field where everyone else is. The kids begin to suspect something when they realize that a real Pokéblock Taster would know that Tamato Berries are hot. Some Pokéblocks fall out of James’ bag and the kids realize they’ve been chasing the wrong culprit. Jessie arrives and swipes Pikachu with the net. Jessie and James then say their motto again, James with swollen lips. Combusken uses a Fire Spin and scorches Jessie’s bag of Pokéblocks as Pikachu jumps from the rising balloon. Pokéblocks start to fall back to the ground; Munchlax jumps up the stream of Blocks to the balloon and starts eating out of the bag. Jessie gets aggravated and throws the bag overboard; Munchlax dives after it.

May tries to catch Munchlax and ends up being dug a couple inches into the ground. Ash sends out his Snorunt and calls for an Ice Beam. It ends up hitting the tree next to Team Rocket’s balloon and it creates an ice pillar with spikes sticking out of it. Team Rocket begins to gloat that it missed but the balloon hits a spike and pops, sending Team Rocket blasting off again! Pokéblocks continue to fall to the ground and Munchlax continues to gobble them up. The kids watch in amazement as Munchlax keeps eating while Ash tells May to throw a Pokéball. She does, and Munchlax turns to see it coming. Opening its mouth, Munchlax eats the Pokéball. May droops her head saying “You ate the Pokéball…” Suddenly, Munchlax disappears and the Pokéball appears in the air. The Pokéball drops to the ground, wiggles for a few seconds, and then stops. May is first surprised and then happy that she caught Munchlax; she walks over and picks up the Pokéball, hugging it happily.