The Digimon StoryThis tutorial gives you an overview of the stories of each of the 4 Digimon seasons.
7 kids (Tai Kamiya, Matt Ishida, Sora Takenouchi, Mimi Tachikawa, Izzy Izumi, Joe Kido and T.K. Takaishi) are at summer camp in Japan when it starts to snow. The kids are transported into the Digital World, where they meet their Digimon partners, at the In-Training Stage. There are good Digimon running around File Island that have turned evil because of Black Gears, which embed themselves in the Digimon and take over their thinking. It's the kids' job to destroy these Black Gears and the evil Digimon that's sending them out, Devimon. In the process, they're told that they are the children of legend, the Digidestined, who will save the Digital World. The Digidestineds' Digimon partners digivolve to higher levels to fight with stronger attacks.
Little T.K.'s Digimon, Patamon, is the last Digimon to digivolve, and he's always upset that he can't digivolve. He finally manages to digivolve to destroy Devimon, but uses up all his energy in the process and reverts to a Digi-Egg.
Later, the children meet an old codger named Gennai and find out that they have to go find the crests and tags that will let their Digimon digivolve even further. They go to the continent of Server and find the crests and tags over several episodes.
On their return to File Island, Gennai tells the Digidestined that there's another Digidestined kid back in the real world, and Myotismon, a new enemy, is seeking her out to destroy her. They return to Earth and discover that the 8th child is Kari, Tai's little sister. Kari gets her Digivice, crest and tag, and partner, and Myotismon rises as VenomMyotismon. To fulfil a prophecy uncovered by Gennai, Angemon and Angewomon attack Tai and Matt so their Digimon partners will digivolve to Mega level and defeat VenomMyotismon.
When they go back to the Digital World, years have passed and the world is now under the rule of the 4 evil Dark Masters. The Digidestined manage to defeat all but one of these evil Digimon, Piedmon. Piedmon turns all the kids and Digimon except T.K., Kari and Patamon into keyrings, and with T.K.'s help and the power of Hope, Angemon digivolves to MagnaAngemon to save the day.
The Dark Masters are defeated, but there's still one more Digimon to overcome: Apocalymon, the Digimon behind the Dark Masters. He traps the Digidestined and takes their crests and tags, leaving them helpless. Just as all seems lost, the kids find the power of the crests in their hearts. Now, their Digimon partners can digivolve, but they still aren't powerful enough to destroy this threat. As Apocalymon prepares to release his Total Annihilation attack, light shoots from the Digidestineds' Digivices to destroy the attack and Apocalymon.
The kids' work is done, and they say a last goodbye to Gennai and the Digimon, taking the rail car (o_O) back to Earth.