Satoshi and Iris walking on a dirt path road are seen fighting over who is following who. Each speeding up continuously to prove so. Iris asks Satoshi why he should lead if he isn’t even familiar with Isshu, and he should be grateful she is guiding him. While facing off they notice a Pokémon staring at them, none other than Mijumaru.
Mijumaru tries to calm down the situation, but Satoshi and Iris are more worried about the Pokémon. They realize it is the same Mijumaru that saved them before from Team Rocket. Satoshi uses his Pokédex to scan Mijumaru. It tells Satoshi that Mijumaru can use its shell as a scallsword. Satoshi thanks Mijumaru for the help before. The otter Pokémon runs to Satoshi and Pikachu explains Mijumaru has been following them around. Absorbed by its cuteness Iris grabs Mijumaru and begins to pinch the uncomfortable Pokémon’s cheeks. It denies Iris and jumps on top of Satoshi’s shoulder, dumping Pikachu in the process. Iris wonders if Mijumaru likes Satoshi and as a reaction Pikachu immediately uses Thunderbolt on Mijumaru. Quickly responding it uses its shell to guard itself making the attack bounce onto Satoshi. Iris and Kibago just laugh at the situation. She wonders if this Mijumaru just wants Satoshi to capture it. Satoshi agrees and runs off and throws his Pokéball. But to his dismay it only manages to hurt Mijumaru and land on the floor. Satoshi wonders, then asks if it could happen to be Prof. Araragi’s Mijumaru, and Mijumaru responds happily.
Knowing the situation they run to the nearest telephone station where Satoshi tells Prof. Araragi what happened. She had been wondering where it had gone as was glad Mijumaru was safe. She asks if Satoshi could take care of the Pokémon. He agrees and Prof. Araragi sends Mijumaru’s Pokéball over the transfer device. He turns off the station but Mijumaru has disappeared. They run to look for it but before they can get far they fall into a mysterious hole. A kid comes from above the whole and explains the hole is Meguroco’s doings.
Team Rocket appears in overcoats, sunglasses, and hats rushing quickly but falling into a similar pitfall as well before getting very far. A Meguroco with sunglasses inside the hole angrily greets Team Rocket.
Satoshi’s Pokédex is seen revealing Meguroco’s Pokédex entry. Glad for his help they greet the boy. He reveals his name is Dan and his family owns a spa resort hotel. Iris is glad to hear this but Dan also explains that Meguroco has been causing problems at his resort.
There are trees and holes all over the floor at the resort’s sand bathes. He explains, while people were resting in his sand bathes many Meguroco would rest in the sand. But then all the Meguroco would throw sand as they went underground and would scare the customers away. Iris wonders why the usual docile Meguroco would suddenly act in such a way. In order to “investigate” Satoshi and Pikachu quickly get themselves on the sand and begin to rest. Iris protests but from the floor Kibago pops out and bathes too. Team Rocket is then shown spying on Satoshi and Co. but while doing so Meguroco is threatening them from the behind.
Meguroco quickly goes underground and heads for Satoshi. Reminding Satoshi that he is still looking Mijumaru Satoshi stands up. A faint “Miju” is head from the other side of the bath. Resting on a pillow is Mijumaru with its shell on its forehead. Meguroco is then shown jumping from the floor and landing in front of Satoshi and Co. The kid points out the Meguroco with glasses is the leader of the Megurocos. The Pokémon jumps and captures Kibago with its mouth. Satoshi orders a Thunderbolt but Iris stops him before he can attack. Using Thunderbolt would also harm her Kibago. She runs over to Meguroco and grabs it by its neck in an attempt to release Kibago. Satoshi, Pikachu, and Mijumaru run over to help out their comrade. Pikachu’s ear goes inside Meguroo’s nostril as they are trying to push Kibago out and it causes Meguroco to let go. But immediately it jumps in the air grabbing Pikachu by its arm and Mijumaru by its foot in the process. Meguroco tries to run away but is lifted by a magnet before he can get any further. Team Rocket reveal themselves within the crane that is holding the huge magnet.
Satoshi demand they let Meguroco go. But Team Rocket wouldn’t give it away that easily and they go no their way. Nyarth throws an explosive on the floor to slow them down. Team Rocket stops for a second and the floor around their vehicle begins to tremble. Meguroco from all over begin appearing. Satoshi and Co. catch up to find Team Rocket surrounded by several Megurocos and their crane slowly sinking into the ground. Team Rocket manages to jump out in time. But the magnet keeping Meguroco up is released and it begins to walk away. Team Rocket flees knowing they can’t do anything about the situation.
The Meguroco drops Pikachu and Mijumaru off on the floor where several frightened Minezumi, Mamepato, and Shikijika are at. Satoshi and Co. watch from behind a rock. The leader Meguroco makes a speech but is interrupted by a geyser. After some more talking the frightened Pokémon move along despite several geyser’s sprouting everywhere. Dan notes that geysers have never appeared before. Everyone begins to wonder if maybe the reason he rampaged at the sand bath was because it sensed this danger was coming. Satoshi calls Pikachu and all of a sudden the ground begins to tremble. A series of geysers circle the frightened Pokémon and a small river is formed, stranding them all on a small platform. As Satoshi runs over to help Pikachu also runs towards the platform, but Mijumaru throws Pikachu onto the floor preventing Pikachu from going on. Satoshi runs for the river but the boiling water quickly makes Satoshi jump back.
The Meguroco with sunglasses calls all the other Meguroco. He bites a tiny boulder that is grounded to the floor and lifts his body up. A second Meguroco climbs him and lifts his body up. Several Meguroco do this creating a pseudo-bridge. After the last Meguroco gets on they fall backwards landing on the platform, creating the bridge to set the stranded Pokémon free.
Satoshi tells them to come over, but they are too scared. The determined Satoshi climbs over to the platform and encourages the Pokémon. A Shikijika is the first to go. The Minezumi follow and the Mamepato fly to the other side. Pikachu goes too, but immediately after Pikachu jumps over the floor underneath the Meguroco on the platform beings to crumble. Satoshi manages to capture it by its tail in time. While Satoshi is keeping the bridge going so everyone can get off, and suddenly a nearby geyser sets off aiming directly at Satoshi. Mijumaru responds and jumps and uses its Water Gun to counter the geyser. Mijumaru begins to fall, but Satoshi is able to recall it back to its Pokéball in time. But because of this Satoshi became distracted and lost his grip on Meguroco. Out of no where a hand grasps Satoshi’s hand. Iris had grasped her legs around the last Meguroco and grabbed Satoshi’s hand before the bridge could collapse. The first Meguroco then lifts the entire bridge vertically again. The entire bridge collapses, but everyone is ok and laughing.
The scene cuts to Iris, Satoshi, and all their Pokémon in a taking a bath in the new hot springs. Dan and his Father explains the geysers destroyed any chance of sand baths but have left hot spring bathes an option. The Meguroco with sunglasses then appears off to the side coming out of the floor and laughing.
