Ash Ketchum (Veronica Taylor in the English Adaption) is finally 10 years old, old enough to become a Pokémon Trainer. He wakes up late on the day he is supposed to receive his first Pokémon at Professor Oak's lab, however, and arrives to discover all the Pokémon are gone. Ash has no choice to take a naughty Pikachu (Ikue Otani in both Adaptions (Japanese & English)). Pikachu will not listen to Ash or go inside its Poké Ball, so Ash must drag it along with a rope. After many failed attempts at capturing some Pokémon, Ash throws a rock and hits a Spearow. The Spearow gets angry and the entire flock starts chasing Ash and Pikachu. They run away from the Spearow, borrowing a bike from a red-haired girl named Misty (Rachel Lillis in the English Adaption) to escape, but when they cannot go any farther, Ash uses his body to shield Pikachu from the attacking Pokémon. Pikachu realizes how much Ash cares for him and uses a powerful electric attack to drive the Spearow away, destroying the bicycle in the process as well. Ash and Pikachu see a glimpse of Ho-Oh.

• Note: The 1st Appearances of Ash Ketchum, Delia Ketchum (Ash's Mother), Prof. Oak, Gary Oak & Misty.
• Event: Ash Starts His Journey, And Then, He Gets A Reculant Pikachu.

Finally arriving in Viridian City, Ash is cornered by Officer Jenny (Lee Quick in the English Addaption) who asks why he is carrying Pikachu instead of having it in a Pokéball. After explaining, Jenny takes Ash to the Pokémon Center where Nurse Joy (Megan Hollingshead in the English Adaption) begins treatment on the injured Pikachu. Before Pikachu's treatment finishes, however, Ash is interrupted by Misty, the girl who Ash took the bike from, who vows to stick with Ash until he pays her back for destroying her bike. The Pokémon Center is then attacked by Jessie (Rachael Lillis in the English Adaption), James (Ted Lewis in the English Adaption), and their talking Meowth (Nathan Price in the English Adaption), members of Team Rocket, seeking to steal all of the infirm Pokémon. Ash's Pikachu and the Pokémon Center's many Pikachu manage to defeat Team Rocket by shocking them using Thunder Shock, sending them 'blasting off' into the sky for the first time.

• Note: The 1st Appearances of Team Rocket, Officer Jenny & Nurse Joy. The 1st Appearance of Misty's Goldeen.

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. Ash also captures a Pidgeotto. Team Rocket shows up to steal Pikachu and Pikachu and Pidgeotto are weakened by Koffing and Ekans, so Ash reluctantly sends out Caterpie. To the surprise of Jessie and James—not to mention Ash—Caterpie's String Shot is able to defeat the Team Rocket Pokémon, including Meowth! When Misty tries to make nice with Caterpie, it evolves into a Metapod.

• Event: Ash Catches Caterpie and Pidgeotto. And Then, Ash's Caterpie Evolves Into Metapod.

While wandering through Viridian Forest, a Samurai challenges Ash to a battle, and it turns out to be Metapod vs. Metapod. After a short time, a swarm of Beedrill attacks, and Ash's Metapod is taken by them. Ash is able to rescue his Metapod and it evolves once more into Butterfree.

• Event: Ash's Metapod Evolved Into Butterfree.

Ash, Pikachu, and Misty finally reach Pewter City and meet Flint, a mysterious man who sells rocks. Ash is ready to challenge the Pewter City Gym Leader, Brock (Eric Stuart in the English Adaption) for his first Badge, but loses the battle. Flint takes Ash and Pikachu to Brock's home and Ash learns that Brock cares for his many younger brothers and sisters since their dad left them. He then brings Pikachu and Ash to a watermill to make Pikachu stronger. Ash battles Brock again, this time coming closer to winning. A fire breaks out in the gym, however, and the sprinklers go off, weakening Onix. Ash wants to defeat Onix but is held back by the thought of Brock's siblings (when he opens his eyes he finds he was literally held back by them). Ash leaves the Gym but Brock catches up to him and gives Ash the Boulder Badge. Flint turns out to be Brock's father and takes over the Gym and the responsibility of his children for Brock when he decides to join Ash on his journey.

• Note: The 1st Appearance of Brock. The Appearances of Brock's Onix & Geodude.

Ash, Misty, Brock, and Pikachu arrive at Mt. Moon to find Team Rocket interfering with the local wildlife in hopes of finding the rare Moon Stone. With the help of Seymour the Scientist, the gang saves the Moon Stone and the Clefairies that guard it. Also, Brock catches a Zubat.

• Event: Brock Catches a Zubat.
• Note: The 1st Appearance of Misty's Staryu.

In his quest to collect Gym Badges, Ash heads for Cerulean City, intending to confront the Cerulean Gym Leader. For some reason, Misty expresses a desire to avoid Cerulean City and disappears along the way. Upon entering the gym, Ash and Pikachu are entranced by a synchronized swimming show being performed by three beautiful sisters, unsure if he has really found another Gym. The three reveal that they are the Gym Leaders but have since converted the Gym into an aquarium and water show, and offer to just give Ash the badge, but Misty appears once more, revealing that she is also one of the Gym Leaders and will battle Ash in lieu of her three older sisters. However, Team Rocket disrupts the battle in an attempt to steal all of the Gym's Pokémon, and Misty's sisters decide to award Ash the Cascade Badge for helping save everyone.

• Note: The 1st Appearance of Misty's Starmie.

Ash and friends are still on their way to Vermilion City and still lost. They stop by a pond for a break when they see an Oddish taking a drink. Ash and Misty try to catch it but they are stopped by a mysterious Bulbasaur who rescues the Oddish. They continue on their journey and keep getting caught in traps, until the Bulbasaur's owner, Melanie, finds them, saves them and brings them back to her cabin. It turns out that she helps injured, sick, and abandoned Pokémon, and they decide to help. Meanwhile, Team Rocket decides to steal all the Pokémon, while Brock wonders if he should stay with Melanie. In the end, Melanie gives Bulbasaur to Ash, but not until Bulbasaur challenges Ash and Pikachu to a battle.

• Event: Ash Catches a Bulbasaur.

While on the road to Vermilion City, Ash, Misty, Brock, and Pikachu come across a Charmander sitting on a rock. Ash tries to catch it, but it turns out it has a trainer and cannot be captured, so they head to the Pokémon Center. At the Pokémon Center, a hotshot trainer named Damian is bragging about how he left his Charmander behind, promising to come back for it when he means to abandon it for being weak in his eyes. After hearing this, Ash and Brock head back out to get the poor Pokémon as a rainstorm threatens its very life. After a battle with Team Rocket, where Damian witnesses Charmander defeating them, Damian tries to get Charmander to come back to him, but the Pokémon's loyalty now belongs to Ash. Ash captures Charmander, gaining a new friend and Pokémon.

• Event: Ash Adopts Charmander.

Ash, Misty, Brock, and Pikachu become the victims of pranks played by a gang of Squirtle known as the Squirtle Squad. They end up falling down a hole, and are even eventually captured by them. It turns out that they are working together with Team Rocket. When Pikachu is severely injured, the Squirtle lets Ash out to get medicine from town, but must return soon or his friends will be trapped by the Squirtle Squad forever. In the end, the Squirtle Squad saves the town from a fire started by Team Rocket and Squirtle joins Ash on his further adventures.

• Event: Ash Catches Squirtle(Which is the Leader of the Squirtle Squad).

When a Krabby that Ash catches disappears, he goes to a nearby lighthouse to see if it reached Professor Oak's lab. The keeper of the lighthouse is Bill, a Pokémon researcher who is searching for a mysterious Pokémon that sometimes appears by his lighthouse. Just as this mysterious Pokémon answers Bill's call and approaches the lighthouse, Team Rocket appears and tries to capture it. Injured, the Pokémon loses its trust of Bill and vanishes forever, though Bill intends to keep an eye out in case it ever appears again.

• Event: Ash Catches A Krabby, When It Went Straight to Prof. Oak's Lab.

After being hit by a Dragon Rage attack from James' newly evolved Gyarados while at sea, the humans are separated from their Pokémon on an island that is inhabited by giant Pokémon. Pikachu, Bulbasaur, Charmander, Squirtle, Meowth, Ekans, and Koffing try to make their way back to their trainers, while the trainers and their Pokémon escape the giant Pokémon, unaware that they have all landed on an island owned by Team Rocket to house a theme park dedicated to a giant robotic Pokémon.

Ash and his friends have finally arrived in Porta Vista, a beachside tourist town. After destroying an old man's ship, they must help in the old man's business. To attempt to pay the man back faster, Misty enters a beauty contest, only to discover she is competing against Jessie and James (with fake breasts - All scenes with this were cut in the U.S. airing, when it was finally aired).

Stuck in Porta Vista because they missed the boat, Ash and friends sit around waiting for the next boat and witness a great explosion. They later discover that it is a group of Tentacool that is attacking the city since construction is destroying their reef. Misty manages to appease the giant Tentacruel. She catches a Horsea that was being harassed by the Tentacool.^[c]

• Event: Misty Catches a Horsea.

As the group continues on their way to Saffron City, they notice a flock of Butterfree out over the ocean. Brock informs Ash that it is the mating season for all of the Butterfree. Ash decides to release his Butterfree so that it can mate. However, Team Rocket has plans to steal them all. Ash's Butterfree bravely frees all the Butterfree and in the end, Ash releases it.

• Event: Ash Released Butterfree to be with the pink Butterfree.

As Ash is on his way towards Celadon City, he encounters a Mankey. The Mankey starts chasing him and steals Ash's hat. Ash tries to get it back and fails. Team Rocket arrives to get Pikachu and when Mankey walks by, James kicks it away and in its anger, evolves into Primeape. After remembering the poem Professor Oak said, Ash captures it.

• Event: Ash Catches a Primeape.

Ash and his friends arrive at a town where many of the town's children are disappearing. They discover that a Hypno, a hypnotic Pokémon, is responsible. Adults in the town have come to help their insomnia by being put to sleep by Hypno. However there is a side effect, making the children think they are different Pokémon and run away and put real Pokémon to sleep. Ash stops Team Rocket from stealing Hypno and uses the Pokémon Drowzee to bring all the children and Pokémon back to normal. A useless Psyduck follows Misty around, and after she drops a PokéBall, Psyduck activates it and captures itself, much to Misty's dismay.

• Event: Misty Catches Psyduck.

Note: The flashback was originally from 'Pokémon – I Choose You!' in the original Japanese and the flashback was changed with 'Beauty and the Beach' (which was aired on June 24, 2000 in the United States) in the English dub.

Team Rocket plans a scheme to steal many Pokémon by opening a grooming shop. Ash and his friends meet Susie, a famous Pokémon breeder. In the end, Brock gains a Vulpix when Susie tells him to look after it as she goes off to learn more about Pokémon breeding.

• Event: Brock catches a Vulpix from her original trainer, Suzie.

After meeting Rebecca, a girl whose father Anthony is more concerned about training his fighting Pokémon Hitmonchan at the gym instead of Rebecca, Ash enters a Fighting Pokémon-only tournament with his Primeape. Team Rocket also enters and resorts to cheating, stealing another man's Hitmonlee, in order to win. After learning how much his daughter means to him and losing, Anthony promises to train Ash's Primeape, the tournament's winner, to make him stronger, so Ash gives it away and promises to return.

• Event: Ash Gives Primeape Away at The Pokemon-Fighting Tournament.

The group arrives in Gringy City where everything is dark and gloomy. A Magnemite follows Pikachu everywhere ever since he caught a peculiar illness. Grimer and Muk block a turbine in a local power plant, which causes the power in the Pokémon Center to go out. Ash captures Muk and Pikachu is cured of his cold.

• Event: Ash Catches a Muk. And Then, Sends It to Prof. Oak's Lab.

Ash and his friends get challenged by Team Rocket in seeing who can capture the most Pokémon within the Safari Zone, with Ash catching a whole herd of Tauros. As soon as Ash and his friends head out Pokémon hunting, Team Rocket manages to get the drop on the game warden (Mr. Kaiza) and forces him into giving up the location on where Dratini is (the Dragon Valley). In the end, Ash, his friends, Team Rocket, and Kaiza end up seeing the legendary Dratini and Dragonair, with the heroes saving the day.

• Event: Ash Catches All 30 Tauros. And Then, Send All Of Them to Prof. Oak's Lab.

This episode was deemed controversial, due to the use of guns, which causes confusion because Ash captures thirty Tauros.

Satoshi and his friends arrive at Pokémon Center where the Monster Ball transfer machine has been causing problems, as the transferred Pokémon never end up at the other side. Satoshi and his friends decide to accompany Porygon, a computerized Pokémon, used by Professor Akihabara to investigate the problem, only to discover that Rocket Gang and another Porygon are to blame.

When at a carnival, Ash and his friends meet Melvin, a magician who is really losing his touch and fails in his own magic show. In his effort to get better, Melvin decides to hypnotize Ash and uses his Pokémon Exeggcute to capture loads of Exeggutor. The Exeggutor end up hypnotizing themselves and Team Rocket and almost destroy the entire carnival. The carnival owner sets a time bomb to stop the Exeggutor. Ash's Charmander uses flame attacks and Melvin successfully performs his fire magic trick to wake up the Exeggutor before they get harmed by the time bomb. After this Charmander unexpectedly evolves into Charmeleon.

• Event: Ash's Charmander Evolves Into A Charmeleon.

Arriving at a canyon to find an old fashioned fossil hunt, Ash, Gary and the gang decide to join in. But Team Rocket arrives and intends to blow the canyon up. Ash, Pikachu, and Team Rocket fall into a pit which is full of awakened ancient Pokémon. Their only hope rests in Ash's disobedient Charmeleon, which evolves into a powerful, yet still disobedient Charizard to defeat a raging Aerodactyl. In the end, the ancient Pokémon are sealed away once more (along with a terrified Team Rocket) and Officer Jenny dismisses the entire event as a side effect caused by Jigglypuff's singing. Ash, however, finds a rare Pokémon egg in the chaos and keeps it.

• Event: Ash's Charmeleon Evolves Into Charizard.

When the egg Ash found hatches into a brand new Pokémon, Togepi, everyone wants to own it. They decide to have a small Pokémon Tournament. Ash, who found it, claims he should be the one to keep it. In the end, Ash wins the tournament, but since Misty was the first person Togepi saw when he hatched, he thinks she is his mother and stays with her.

• Event: Togepi Hatches. And Then Misty Takes Care of It as A Mother.

Upon returning to Cerulean City, Misty is asked by her sisters to help out with a new underwater show. She decides to help for this underwater play with her Pokémon, but Team Rocket arrives and try to ruin things. At the end of the episode, Misty leaves her Starmie and Horsea with her sisters to assist in further shows.

• Event: Misty left Horsea and Starmie at Cerulean City.

Ash enters his first match of the tournament on the water field against Mandi the Astounding. During the battle against Mandi's Exeggutor, Ash's Krabby evolves into Kingler, who he then uses against Mandi's remaining Seadra and Golbat, winning the match and moving onto the next preliminary round.

• Event: Ash's Krabby Evolves Into Kingler.