Pokémon (ポケモン, Pokemon?), abbreviated from Pocket Monsters (ポケットモンスター, Poketto Monsutā?), is a Japanese animated series, which has since been adapted for the North and South American, Australian and European television markets. It is somewhat based on the Pokémon video game series and a part of the Pokémon franchise.
Originally a single series, Pokémon, it has since been made into three series, including Pokémon: Advanced Generation and subsequently Pokémon Diamond and Pearl, which sequentially continue the story of Pokémon, while its spin-off Pokémon Sunday (formerly Weekly Pokémon Broadcasting Station) has broadcast a series of stories revolving around some of the recurring characters, Pokémon Chronicles or, as it is known in Japan, Pokémon.
Ash Ketchum (Satoshi in the original Japanese series) has just become a Pokémon trainer in the Kanto Region. He picked Pikachu because, after breaking his alarm clock, Ash was late for his appointment and all the conventional starter Pokémon (Bulbasaur, Charmander and Squirtle) were gone. He has a childhood rival named Gary (Shigeru in the original Japanese series). Ash accidentally destroys a bike belonging to a girl named Misty (Kasumi in the original Japanese series), who starts to follow him to get her bike back, but soon becomes a close friend. Misty endeavors to be a great water Pokémon trainer. Shortly thereafter, Ash battles Brock (Takeshi in the original Japanese series), the leader of the Pewter City gym. Ash initially loses to Brock's Onix, but wins the Boulder Badge in a rematch. Brock then turns over gym leader duties to his estranged father and accompanies Ash and Misty on their journey with the goal of becoming the world's greatest Pokémon breeder.
Ash's Kanto journey culminates with him collecting the necessary eight badges to compete in the Indigo League Pokémon Tournament held annually on the Indigo Plateau in Viridian City. Upon his arrival Ash shrugs off repeated suggestions that he should spend his time training and preparing for the tournament. He ultimately loses in the quarter-finals to Richie, a new rival who happens to use many of the same Pokémon as Ash, including a Pikachu named "Sparky".
After the Indigo League, Ash returns briefly to Pallet Town before setting out on a new journey to the Orange Islands where he will compete in the Orange League. Brock eventually parts company with Ash and Misty to pursue Pokémon research with Professor Ivy. At this point a new character, Tracey Sketchit (Kenji in the original Japanese series) joins Ash. Ash collects four badges and competes against the Orange League champion, Drake, a very experienced trainer. The battle comes down to Pikachu versus Drake's Dragonite with Pikachu delivering a devastating Thunder attack to score the knockout blow.
 Season 3-5
Victorious in the Orange League, Ash again returns to Pallet Town where he and Misty are reunited with Brock who leaves Professor Ivy for an unknown reason. Tracey decides to stay in Pallet Town to work with his idol, Professor Oak. As Ash, Brock and Misty head west to the distant land of Johto. Pokémon: The Johto Journeys marks the introduction of a new series of Pokémon beyond the original 150 named and frequently seen throughout the Kanto and Orange Islands regions.
In 5th season, Ash is defeated by a Pokémon trainer from the southern land of Hoenn region and decides to journey there next after a brief visit home. Before arriving in Pallet Town, Misty receives a message from her sisters requesting that she return to Cerulean City to take over gym leader duties. Brock then decides that he has been away from home too long and must return to help his father take care of his many brothers and sisters. This marks the last time to date that the original trio of friends journeys together.
 Season 6-8
Back to Pallet Town, Ash receives a more modern-looking outfit from his mother and sets out for the Hoenn region with only Pikachu, choosing to leave his other Pokémon with Professor Oak.
In Hoenn, Ash meets May (Haruka in the original Japanese series) and her younger brother Max (Masato in the original Japanese series), who join in his journey. May is excited by the Pokémon Contests that take place in Kanto and Hoenn, while Max joins the group to gain experience so that one day he will have his own Pokémon and become a Gym Leader like his father Norman, the Gym Leader of Petalburg City. Having solved his family issues, Brock returns (also in a new outfit) to accompany Ash. This season, Gary leaves his promising career as a Pokémon Trainer to become a Pokémon researcher. Misty visits the group and takes Ash, Brock, May and Max to the Togepi Kingdom. Finally, Ash participates in the Hoenn League and May in the Grand Festival.
 Season 8-9
After Ash completes the Hoenn League and places in the Top 8, he returns home to Pallet Town, as do May and Max return to Petalburg City, and Brock returns to Pewter City. Ash meets up with Misty, Tracey, Professor Oak and his mother at his homecoming celebration. Professor Birch and Max arrive in Pallet Town that same evening, and May and Brock arrive the next day. Ash and May learn of the Battle Frontier and the new contests in Kanto region and decide to travel together to compete. Brock, Max and Misty decide to join them on their new journey, however, Misty leaves the group again in the next few episodes to return to looking after the gym.
 Season 10-13 (Continue)
After Ash becomes champion of the Kanto Battle Frontier, May as well as Drew, Solidad and Harley travel to the Johto region to participate in the Grand Festival held there. Max returns to Petalburg City to get ready for his own Pokémon journey and Brock returns to Pewter City, once again. Ash learns of a new region called Sinnoh, where he embarks on a new journey. Ash planned to bring only Pikachu, but Aipom snuck on the boat. Brock comes back a few days later in Sinnoh and they both meet Dawn (Hikari in the original Japanese series), a new trainer who hopes to become a great Pokémon Coordinator, like her mother. Ash meets a new rival, Paul (Shinji in the original Japanese series), who prefers to capture the strongest Pokémon, leaving the weak who are released, in strong contrast to Ash's methods. During the journey, Ash encounters the Elite Four of Sinnoh Region in different places respectively, he carries on battles with them, and also receives their instructions about battle techniques. May briefly returns and travels with Ash, Dawn, and Brock to the Wallace Cup, and Ash meets Gary several times throughout their journey.
Then, after Ash gets in to Hearthome for his 5th badge, he runs into Barry (Jun in the original Japanese series), he is commonly running into them on and off. Barry and Ash have battled against each other twice, once at his anime debut, and then for the right to challenge Palmer to finish off the Twinleaf Festival. At Lake Acuity, Ash begins his full battle with Paul and wholly defeated by him, this extraordinary experience makes him try harder to beat Paul next time, in the Sinnoh League. Furthermore, Dawn gets her 5 ribbons and enters the Grand Festival, accompanying Zoey, Nando, Jessilina, Ursala and Kenny. After several rounds of competing, Dawn and Zoey enter the final round and carry on the final battle, and Zoey defeats Dawn again.
With the Grand Festival over Ash had his battle with Gym Leader Volkner and gained his eighth, also the final badge. Later the Sinnoh League is being held in Suzuran Island, Ash participates in it and wins his first-round battle against Nando, and he will fight against Conway in the third round.