Ash's mom and a lot of their neighbors have gotten together at Professor Oak's lab to watch the Pokémon League battles unfold. As the announcer speaks, they see Ash and his friends walk by in the background. They all cheer.
At the stadium registration area, Ash checks in at one of the many desks. Brock immediately falls in love with the girl there and makes this fact very visible, not only embarrassing Ash and Misty but the girl as well. As Misty pushes him off, Ash gives his Pokédex to the girl. She sticks it into the computer, hits a few keys, and hands it back to him, saying that he's all checked in. He asks her who he's going to be battling in Indigo Stadium and Brock reappears, telling him that he won't be going there just yet. He tells Ash that he has to win a battle in four different fields (Water, Grass, Rock, and Ice) to go on to Indigo Stadium. Ash asks him how he knows and he whips out the Pokémon League Trainer's Book. He embarrasses the girl once again, and is once again shoved off by Misty. Ash asks the girl where he'll be battling first, and she tells them to push the button on the desk and a light will stop on the field. He hits it and the light stops on the Water Field. The panel then shows his opponent: a long-haired guy whose name is Mandy. After she tells him that he'll be in the third battle there that day, they leave.
Outside, Team Rocket, disguised as reporters, are interviewing trainers, trying to find someone with rare Pokémon that they can steal. After talking to someone with a Dodrio, Venomoth, and Raticate, they are starting to get discouraged. Suddenly, they notice Mandy doing a little performance with a large crowd around him and decide that he looks like a prospective target. They approach him, but he snubs them, saying he can't believe they haven't heard of him. He asks them what network they're from and the reply that they're from LCN: Lovely, Charming Network. Mandy walks off, telling them that he'll only be interviewed by "networks with viewers." Team Rocket is very ticked off, and James and Meowth restrain Jesse from getting some revenge.
Elsewhere, Misty asks Ash if he wants to borrow some of her Pokémon, but he feels that Squirtle will be able to do the job. They hear a familiar voice and turn to see Gary sipping some tea surrounded by his cheerleaders. He tells Ash that he's going to be battling on the Ice Field and wishes him luck on his first battle, only to say that it's because he wants to be the first to beat him. He laughs and walks off to his first battle. Suddenly, Ash is paged over the P.A. System and is told to go to the nearest courtesy phone, where there is a call waiting for him. He hurries over to one and picks up the receiver. It's Professor Oak, and he asks Ash if he'd like Krabby to balance out his team. Ash eagerly consents and Professor Oak hurries off to send Krabby to him. Meanwhile, his mom comes into view and asks if he's ok. She moves the camera a little to show all the other people at Oak's who are cheering him on and Ash is a bit flattered. The Pokéball containing Krabby appears on the stand beside the phone and Ash thanks Professor Oak. After some last-minute reminders from his mom and a cheer from the others, Ash hangs up. As he walks out of the center, he meets Mandy for the first time. He introduces himself, but makes fun of Ash, saying that he'll be no match for him. Ash vows to beat him.
During lunch, Misty asks Ash if he really wants to use Krabby in battle, as he hasn't ever fought before. Brock agrees with her, saying that many matches are decided before they start as people choose the wrong Pokémon to use. He tells Ash that the decision is up to him. They hear a lot of cheering coming from a nearby television and see that Gary has just won his first battle. Ash looks determined to keep his reputation.
Later, Ash and his friends have made their way to the Water Field, where someone has just beat a Tentacruel with a Seaking. Misty notices that Ash is shaking slightly, but he says that it's just the vibrations in the stadium. The doors open and Ash steps onto the field and onto his podium. The announcer introduces Ash and Mandy, who turns out to be a league favorite. The announcer then tells them that they only get three Pokémon each, and the battle starts. However, just before they send out they're Pokémon, Jessie's voice sounds over the speakers. She and James tell Ash to beat Mandy, but are quickly carted off by four Officer Jennys. The battle resumes.
Mandy sends out Exeggutor and Ash sends out Krabby. Misty maintains that this is a bad idea, but Ash is confident. Exeggutor sends out a Psywave which Krabby dodges by jumping into the water. Exeggutor forms a whirlpool in the water with a Psychic attack, and Krabby is caught up in it. Ash tries to withdraw Krabby, but the flow of the water makes it impossible. Exeggutor sends out an Egg Bomb attack, and the splashes come back onto him. The announcer raves about how strong Exeggutor must be, being a part grass-type Pokémon and not being weakened by the water. Krabby works his way out of the rushing water and uses a Vicegrip attack on Exeggutor, latching onto one of his leaves. Mandy tries to get his Pokémon to use his Hypnosis attack, but Exeggutor is running around in pain. Krabby unleashes a Leer and then a Stomp, defeating Exeggutor. Brock and Misty express their surprise, and Krabby starts to glow, evolving into Kingler.
Mandy sends out Seadra, who dashes at Kingler with an Agility attack. Neither a Water Gun nor a Bubble attack hits the speedy Seadra and things are looking grim for Kingler. Fortunately, while dodging one rush of bubbles, Seadra hits another and flies into the air. As he falls, Kingler uses a Crabhammer and Seadra is defeated. The crowd starts to cheer for Ash, and Team Rocket looks on with interest. Mandy withdraws Seadra and sends out another speedy Pokémon: Golbat. Brock gets worried, as Kingler has a disadvantage over flying Pokémon. Misty tells Ash to use Pikachu, but he is confident in Kingler's abilities. Kingler jumps into the water and Golbat prepares a Take Down attack. As he swoops down over the water, Kingler surges out and grips him with a Vicegrip attack. Unfortunately, Golbat gets out and hits Kingler with a Razor Wind. Kingler is weakened and Golbat moves in for the kill with a Mega Drain. Just in time, Kingler unleashes a powerful Hyper Beam, hitting Golbat with the full force. Golbat falls to the ground. Ash has won.
Ash cheers and Mandy looks greatly disappointed. Ash runs out onto the platform in the water and gives Kingler a hug, congratulating him. At Professor Oak's, everyone cheers and his mom starts to tear up. Team Rocket is stunned and Meowth says that it's all for the better for now Ash's Pokémon are even stronger. Brock looks in the Trainer Book and reads that winners "should conduct themselves with dignity and restraint." They turn and see Ash dancing in front of the cameras. They all sigh