Ash rushes into Viridian City with his gravely wounded Pikachu. The city's on high alert for Pokémon thieves-thieves like Jessie, James, and Meowth of Team Rocket, a group of bad guys dedicated to stealing valuable Pokémon.

Ash discovers and catches a Caterpie—his first Pokémon capture! Though Ash is excited, Misty is grossed out by Bug-type Pokémon, so she is repulsed by its attempts to be friends with her. At night, as Ash and Misty sleep, Caterpie shares with Pikachu its dream of evolving into a Butterfree.

Misty and Ash continue to wander the Viridian Forest when they spot a Weedle. As Ash battles it, he's distracted by a boy dressed as a samurai and calling himself (naturally) Samurai. Samurai challenges Ash to a battle, and Ash gets the advantage when his Metapod defends itself against Samurai's Pinsir. Samurai sends out his own Metapod—and a standoff begins.

Jessie, James, and Meowth dig a trap for our heroes, but they end up falling into it themselves! Ash and Misty arrive at Pewter City and meet a curious fellow named Flint, who notices that Pikachu is tired and shows them the way to the Pokémon Center.

Will Team Rocket steal the Moon Stone? Are there other Clefairy lurking about, and do they carry Moon Stones, too? And is the legend of the Moon Stone true?

Ash seeks the Cascade badge in Cerulean City—but for some reason, Misty doesn't want to join them. When Ash and Brock show up, the city is buzzing about a break-in that just took place—and are initially accused of the crime!

On the way to Vermillion City, Ash meets AJ, a Gym Leader at an unsanctioned Gym who has 98 wins and zero losses. They battle, and Ash is surprised that AJ's Ground-type Sandshrew can easily beat his Flying-type Pokémon.

While searching for firewood in the foggy woods, Ash and Pikachu discover a bunch of prep-school kids bullying a classmate named Joe.

Ash and Misty, while arguing, discover an Oddish. As Misty's Starmie weakens the Oddish, a Bulbasaur appears and fights Starmie while the Oddish runs off into the woods.