Ash and May are walking down Route 101 on their way to Oldale Town. When May asks why Ash doesn't keep Pikachu in a Poké Ball, Ash simply says it is because Pikachu is his best friend. May wonders if she should do that with Torchic, but Ash suggests looking it up in her Pokédex. She gets it out and tries searching for Torchic, but they then spot an Azurill further down the road. May wants to catch it, so she tries just tossing a Poké Ball and catches the Azurill, but it breaks free. May doesn't know what's going on, but Ash explains that she needs to battle the Azurill and 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 then says to use Peck. Torchic goes full speed at the Azurill, but the Azurill dodges, leaving Torchic pecking another 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 them off by having Pikachu land a Thunderbolt near them. Then, the water trio escapes into a pond.
May checks on Torchic, and Ash says that the next town has a Pokémon Center, so they should hurry there. While they run the rest of the route, May hopes that her Torchic will make it. Along the way the come across a ruin on top of a hill. They go up on top to check out the place when an archaeologist goes up to them. Ash asks if he knows the way to the nearest Pokémon Center. The archaeologist points out to the distance, saying it is just down the road. The two thank him and head on down. At the Pokémon Center, May gives Torchic to Nurse Joy and hopes for the best. Joy says Torchic is okay, but it'll take overnight to restore it. Afterwards, Ash decides to make a call to Professor Oak to tell him where he is and all. 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 Petalburg City Gym Leader and he wants to know what the Gym Leaders are like. But May snaps at Ash, then says that she's hungry and wants to go to the restaurant.
Later, outside in a telephone booth, Team Rocket calls up Giovanni. They tell him that they're in Hoenn, that could mean more opportunities for them. Giovanni isn't too thrilled, since it's the trio who screws up the most. However, Giovanni reconsiders, and since maybe they could take care of Team Magma, he's willing to give them a shot. After he hangs up, he smiles at the thought that they are just in one more area to terrorize. The two start their meals, May comments how good the food is. May's really excited now, seeing how this is what Trainers get. The archaeologist from before happens to be at the restaurant and asks if he could sit down with them. The two don't mind, in fact maybe they could get some info on the ruins. Just outside the Pokémon Center, Team Rocket is digging a hole. They work hard at it knowing they can get Pikachu if they can just get this done right.
Ash and May later meet up with the archaeologist, Professor Alden, again; he apparently has his own office in the Center. He tells them about the Oldale Ruins and how according to legend there are ancient Pokémon to be found there. He notes that there may even be some still alive. Just outside, a Team Magma member spies on them using special goggles. He reports everything is a go and the rest of the group moves in. Back inside, the electricity goes out all of a sudden and then a few Team Magma members with their Houndoom come in. Joy walks by going into the room, but she's caught from behind by another Magma member. One of the members says that they need access to the ruins, and if Professor Alden doesn't comply, they'll do something to the others. He has no choice but to give in. Team Rocket on the other hand digs up, but only find themselves still outside. They are surrounded by grunts, and they send out their Pokémon. However, Team Magma's Houndoom use Roar, sending the Pokémon back into their Balls. With that, Team Rocket runs off.
The group and Joy are thrown into the storage room. Locked in, they try to find a way out and help Professor Alden before anything goes wrong. Pikachu finds a vent, and they can escape from there. Joy tells them to find the master key and get everything back up if they can. Back in the ruins, the grunts continue to pin down Professor Alden with threats, and eventually tells him what to do. They give him a box with four colored orbs, and he knows what to do. Professor Alden puts each on in a wall of one building and it moves, opening the path to a room. The grunts go in to take pictures, but they only find drawings on the wall. The leader says they're out of time, and they leave.
Ash and Pikachu go inside the vent to try to find the way out. Along the way, May stops them, she wants to come along as well. 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 finds it. They follow Pikachu and find a grate where they can escape. Ash kicks down the grate and apparently they aren't too far from the counter. Ash goes up to find the master key while May turns the power back on. Ash goes back and frees nurse Joy, now to find Professor Alden.
They get to the ruins just moments before Team Magma makes their escape on a helicopter, it looks like they're too late for them. They find Professor Alden unharmed fortunately. They ask him what happened and if everything is alright. He says everything's okay, nothing to worry about. Team Rocket behind a rock managed to snag the four orbs, and everything goes well until Wobbuffet makes a big scene. The group notices them and 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 away from Team Rocket. Finally Pikachu finishes them off with a Thunderbolt and sends Team Rocket flying off once again.
Professor Alden recovers the orbs and they all head inside the room. He places the orbs back into the door and soon it glows. The light trails around through lines in the room. The giant block moves, revealing stairs that lead down. They go down and find an underground lake. Soon enough, a Relicanth jumps out of the water and they see that the lake is full of them. Satisfied, Professor Alden thanks the two for their work. Back in the Pokémon Center, Joy gives May her Torchic back, who is feeling all better. May sends out Torchic, who jumps up to May happily.