Ash and his friends make their way through some rugged terrain, still bound for Blackthorn City. Misty complains about the increasing heat. Brock points out that there are volcanoes and hot springs around, which doesn't please Misty at all. Meanwhile, Team Rocket are relaxing in the hot springs when Meowth spots the group walking past. However, Jessie and James return to their relaxation, declaring that the twerps are the reason for their stresses. A huge geyser suddenly erupts beneath the Rocket trio, blasting them off.
Later, Ash and Misty get into a passive-aggressive argument because of the heat. When a Magcargo appears, Ash checks his Pokédex for information on it. Brock then notices more Magcargo around them. Misty remains irritated and urges her friends along, and eventually, the group finds a cooler place. They continue through a narrow mountain pass until they come across a sleeping Magcargo blocking the road. Ash yells at it to move out of the way. As a result, Magcargo wakes up in a foul mood and aims a Flamethrower at them. The group manages to duck in time to avoid the flames, and Magcargo returns to its nap. Ash decides to battle it, but Misty tells him that she'll handle it instead because a Fire-type like Magcargo is weak against a Water-type. She is about to send out Staryu when her Psyduck comes out instead. Psyduck approaches Magcargo and wakes it up. Psyduck is intimidated by Macgargo's rage and rushes behind Misty's legs for safety. Misty is annoyed and calls out her Poliwhirl to douse Magcargo with a Water Gun. Magcargo immediately withdraws into its shell to avoid the water. When it emerges, it retaliates with a Rock Slide. Poliwhirl evades the attacks Magcargo throws at it, but it fails to avoid the Flamethrower attack.
A young boy appears and makes fun of Misty's battle techniques. Misty gets angry at him. The boy declares that he is going to jump off the cliff, although he seems reluctant to do so. When he eventually jumps off, he lands flat on his face. After recovering from his fall, Misty yells at him for making fun of her earlier, but he insults her more. The Magcargo slithers away and the boy blames Misty for that. Misty angrily asks for his name and the boy introduces himself as Egan, the Prince of Fire. Misty proceeds to introduce herself as the Water Princess. The two get into an argument and end up challenging each other to a battle. However, Egan states that he has to chase after Magcargo and rushes off to catch it. Misty yells out at Egan that he doesn't have a chance of catching Magcargo with his Fire Pokémon. Though Ash admits that at least Magcargo has finally moved out of their way. Elsewhere, Team Rocket, while talking about their refreshing day, gets blasted off again when another geyser hits their balloon.
Still sore about Egan, Misty keeps on complaining about him. All of a sudden, Misty and her friends spot Egan coming out of a cave. He asks the group if they saw Magcargo, but Misty replies with sarcasm. Magcargo then appears and Egan sends out his Flareon to battle it. Flareon starts off with a Flamethrower, but Magcargo Withdraws into its shell before following up with a Rock Slide attack. Flareon uses Quick Attack to evade the falling rocks. Egan orders another Flamethrower, but Magcargo once again withdraws into its shell. Magcargo sears Flareon with its own Flamethrower. It prepares to land a Body Slam, and Misty tells Flareon to dodge it. Egan tells her to stay out of his battle and orders Flareon to attack with a Flaming Tackle, which fails. Magcargo then knocks Flareon down. Seeing how badly weakened Flareon is, Misty suggests to call it back, but Egan refuses to listen to her. He orders Flareon to attack once more, but Magcargo counters its flames and finally knocks it out. Magcargo returns to the caves as Egan recalls Flareon back into its Poké Ball. Misty starts to make fun of Egan, and the two start an argument again. Brock suggests that they should eat. When Egan's stomach growls, Misty makes more fun of him. Team Rocket spies on the group from an overhead cliff. They set their sights on stealing Pikachu and the twerps’ picnic lunch to fill their stomachs. Meowth then notices a sudden increase in temperature. The trio turns around to find Magcargo roasting their behinds with a Flamethrower, and they run away from the flames.
During mealtime, Misty and Egan surprisingly start to get along. Misty offers Egan a cup of hot cocoa as Flareon enjoys some Pokémon food. Egan feels guilty for pushing Flareon so hard in battle and says that Flareon is very special to him. After agreeing to stop their rivalry, Egan asks why Misty loves Water types. Misty explains to him that Water Pokémon are very flexible and can easily adapt to any situation. Egan is quick to point out that Misty had no strategy earlier, and she retorts that she shouldn't be so nasty. Later, they encounter Magcargo again. Egan is prepared to challenge it with Flareon. Magcargo attacks with Rock Slide. Egan remembers Misty's advice on being adaptable and he has Flareon dodge the rocks. Egan orders Flareon to use Flamethrower. Magcargo withdraws into its shell again, but this time Egan makes sure not to perform any reckless moves. Flareon Tackles Magcargo into the cliff, causing the wild Pokémon to emerge from its shell a bit shaken. A final Flamethrowers seals the deal, and Magcargo is knocked out. Egan throws out a Poké Ball, and after a few anxious moments, Magcargo is officially caught.
Egan and Flareon’s celebrations are short-lived when Team Rocket steals the Poké Ball using a giant arm. The trio performs their motto with a baseball twist. Misty quickly sends out Poliwhirl and tells it to use Water Gun. Poliwhirl's Water Gun breaks the mechanical arm, releasing Egan's Poké Ball. Team Rocket is not done yet, and call out their Pokémon to attack. Egan sends out his Magcargo. Arbok's Poison Sting attack is taken care of by Poliwhirl's Water Gun and Victreebel's Razor Leaves are singed by Magcargo's fire. After that, Poliwhirl and Magcargo combine their attacks, with the Flaming Water Gun utterly defeating Arbok and Victreebel. Pikachu then uses his Thunderbolt and sends Team Rocket blasting off. Before going their separate ways, Egan and Misty appear to have become friends and promise to have a battle again next time.