WARNING! THE FOLLOWING POST CONTAINS SPOILERS FOR THE POKEMON ANIME. READ AT YOUR OWN RISK!
If I remember correctly, the Pokemon anime has gone on for about 5 season. Here I summarize the story of the Pokemon anime in a single paragraph. Which season? ALL OF THEM!
Our protagonist is a 10 year old named Ash. His home is in Pallet Town. I'd like to draw your attention to the fact, that due to various business reasons, Ash's age will remain 10 even after a million years. He embarks on journey to win the Pokemon League with a single Pokemon Pikachu. To be able to enter the Pokemon League he has to defeat 8 gym leaders and get 8 gym badges. On his journey he captures various Pokemon which he uses from time to time. He meets a girl and his friend, Brock . They travel with him on his journey. On the way, learns of an evil organization whose name begins with a team. Their master plan involves changing the world in one way or another (unless they're Team Rocket) by using a legendary Pokemon. He meets people, new friends and gets a rival. He beats the 8 gym leaders eventually and enters the Pokemon League. He battles a few tough opponents and tries hard (though he should try harder) but eventually fails. But he doesn't lose hope. He says goodbye to Brock and the girl he met on his journey and returns to Pallet Town. He gives all his Pokemon to Prof. Oak (why on earth he does that, I have no idea) and rests for a few days. He then takes his Pikachu and sets out to explore a new region. And thus, the cycle repeats!