Ash prepares to run ahead, while May, a new Trainer, lags behind. He explains that he simply wants to reach Oldale Town before nightfall. However, May spitefully reminds him that she would get to town faster if her bicycle wasn't destroyed, so Ash agrees to walk beside her. As the pair continue to walk along Route 101, May asks why Ash doesn't keep Pikachu in a Poké Ball. Ash simply says it is because Pikachu is his best friend. May Torchic would prefer the great outdoors, but Ash suggests looking it up in her Pokédex. As May reads Torchic's Pokédex entry, she is quickly enchanted by an adorable Azurill further down the road. May wants to catch it, so she tries just tossing a Poké Ball, but Azurill breaks free. May doesn't know what's going on, but Ash explains that she needs to battle the Azurill to wear it down before she can catch it.
May sends out her Torchic to battle. While thinking about Torchic's attacks, Azurill runs with Torchic tagging behind. Azurill manages to get Torchic to run into a tree, May goes over to see if it's alright. The Azurill still wants to fight, Torchic chases after it again. May orders a Peck attack, but Azurill dodges, leaving Torchic pecking at a tree. May says to Torchic that it missed, so Torchic finds and chases the Normal-type Pokémon. Finally, Azurill makes Torchic slam into a rock. Torchic is down, but not out, and manages to chase the Azurill into some bushes. Torchic fires an Ember attack, only to realize that Azurill is now accompanied by an Azumarill and Marill. They all simultaneously spray Water Gun at Torchic, knocking it out in one shot. Ash scares the trio off by having Pikachu land a Thunderbolt near them.
May feels absolutely useless as she cradles her injured Torchic. Though Ash reassures her that a visit to the Pokémon Center will help it heal up. While they run the rest of the route, May hopes that her Torchic will make it. Along the way they come across a ruin on top of a hill, where they meet Professor Alden, an archaeologist who explains that these are the Oldale Ruins. Ash asks if he knows the way to the nearest Pokémon Center, and Professor Alden points them to Oldale Town, just over the hill. The two thank him and head on down. At the Pokémon Center, May gives Torchic to Nurse Joy and hopes for the best. After a quick examination, Joy says Torchic is fine, but it'll need to rest overnight. Afterwards, Ash decides to make a call to Professor Oak to update him on his latest ventures. During the conversation though, May butts in, after all, it is the famous Professor Oak. After the phone call, May pressures Ash to show her around the Pokémon Center. Ash first shows her the rooms that they get to stay in, then the Trainer lobby. Ash overhears a conversation about the new Petalburg City Gym Leader and he wants to know who the Gym Leader is. But May snaps at Ash, then says that she's hungry and wants to go to the restaurant.
Meanwhile, Team Rocket make a call to Giovanni. They tell him that they're in Hoenn and still hunting Pikachu. Giovanni is keen to learn of their progress, but Jessie and the others ask for a cash advance only to get a resounding no. However, Giovanni gives them a task, to set up a Team Rocket branch in the Hoenn region. The trio is left speechless and declare that they received a promotion. After Giovanni hangs up, he informs Persian of his true plan, hoping that the expendable trio will help him to learn more about Team Aqua and Team Magma.
Later Ash and May sit down for their dinners. May takes one bite and she is quickly impressed by the food quality. Professor Alden approaches the pair, happy to see that reached town okay. He sits down to join their dinner table conversation. Afterwards, Alden escorts Ash and May to his research office inside the Center. He informs them that the Oldale Ruins contain a secret chamber, said to be the bridge between the modern era and the ancient Pokémon world. Ash is curious about the ancient Pokémon. Professor Alden explains that he isn't talking about Fossil Pokémon, but rather living examples that haven't changed for millennia. Alden shows the pair an ancient tablet, and he explains that it details how to enter the ruins site, but states that they'll need to wait a bit longer, because it requires four keys that haven't been found yet. Outside, a Team Magma Grunt watches with heat-sensing goggles and affirms that she has sighted Professor Alden. The leading member gives the go-ahead, so the Team Magma grunts move into position. Back inside, the electricity goes out all of a sudden and then a few Team Magma members with their Houndoom confront Alden. Joy walks by going into the room, but she gets caught from behind by another Magma member. One of the grunts says that they need access to the ruins, and if Professor Alden doesn't comply, they'll do something to the others. The Professor has no choice but to give in. Team Rocket, on the other hand, resurfaces from their tunnel, but they find themselves still outside and soon surrounded by Team Magma. Jessie and James order out their Pokémon to attack. However, Team Magma's Houndoom use Roar, sending the Pokémon back into their Poké Balls. With that, Team Rocket runs off.
May, Ash, and Joy are thrown into the storage room. Joy reveals that recovering Pokémon are in danger, and this worries May in particular because her Torchic is currently resting up. Pikachu soon locates a vent. Before Ash crawls his way into the confined space, Joy instructs him to find the master key and restore the electricity. May later joins Ash and Pikachu inside the ventilation shaft. They go on until they find a split, and they are unsure where to go. Pikachu uses his ears to try to find the way out, and he leads them to an exit grate. Ash breaks through the grate with his shoulder and the trio rushes towards the nearby Center counter. Ash retrieves the master key from behind the counter while May switches on the reserve power. The pair free Nurse Joy, who assures them that she will be fine at the Center as Ash and May turn their attention to helping Professor Alden.
Team Magma has since escorted Professor Alden to the Oldale Ruins. A member formally asks the Professor to help them enter the ruin chamber, but he admits that he needs the four treasures to safely enter. The grunt then presents Professor Alden with the four treasures, a set of colored orbs. Alden refuses to comply with their demands, but the grunt reminds him that the people back at the Pokémon Center may pay the price. The Professor follows orders and places the four keys in the correct sequence to unlock the ruin chamber. Team Magma rushes in and takes photos to record the wall glyphs, however, they are disappointed by the findings. The lead member declares the mission yet another failure. Ash and May reach the ruin summit just as Team Magma set off in their helicopter.
The pair are glad to find Professor Alden unharmed, fortunately. Alden admits that he is perfectly fine. Meanwhile, Team Rocket has managed to snag the four orbs, but Wobbuffet's loud voice alerts the Professor and the kids to the trio's presence. makes a big scene. Professor Alden notices they have the orbs. Jessie quickly sends out Arbok, but Ash tells Pikachu to use Quick Attack and soon enough Pikachu's attack hits Arbok and knocks the orbs out of Team Rocket's clutches. Finally, Pikachu finishes them off with a Thunderbolt and sends Team Rocket flying off once again.
Professor Alden recovers the orbs and the trio all head inside the ruin chamber. The sun suddenly rises, shedding beaming sunlight into the stone room. Alden places the orbs back into an internal door and the combination begins to glow. The light trails throughout marked lines in the room. The giant block moves, revealing a hidden staircase leading to a basement area. The trio's curiosity leads them down the stairs and they come across an underground lake. Soon enough, a Relicanth jumps out of the water, followed by several other Relicanth. Satisfied, Professor Alden thanks the two for their work.
Back at the Pokémon Center, Joy gives May her Torchic back, who is feeling all better. May sends out Torchic, who jumps into its Trainer's embrace. Ash asks about the crooks from earlier, and Nurse Joy replies that Officer Jenny is currently investigating. As May and Ash prepare to head off, Professor Alden rushes out of his office to report his latest findings – that people and ancient Pokémon happily co-existed. May is pleasantly surprised by Alden's latest discoveries, and he explains that he now has plenty of work ahead of himself. Later, as May and Ash hit the road now bound for Petalburg City, Ash's attention turns to the Petalburg Gym Leader again. May looks to the side, well aware of the Petalburg Gym Leader's identity, she declares that she is clueless. Ash, however, doesn't notice because he is too hyped for his first Hoenn Gym challenge.