Ep 19. Digimon Adventure 02 19

While the DigiDestined were dealing with the fight against the Daemon Corps, an unknown Digimon appears in the Digital World. The DigiDestined are called to address the situation, but are interrupted when they realize that they have lost their ability to use their Digivices to communicate and transport to the Digital World.

As they attempt to figure out what happened to their Digivices, the group is ambushed by a group of Thundermon who kidnap Ken and Yolei. Davis, Cody, and T.K. are left to figure out how to save their friends without their Digivices. They eventually come across a band of resistance fighters who possess a special device that can transport them to the Digital World.

Upon arrival, they find that the unknown Digimon is Myotismon, a Digimon they thought they had defeated in the past. They attempt to defeat him again, but he proves to be too powerful, and they are forced to retreat.

Myotismon then reveals that he has been manipulating the events of the Digital World and that he is responsible for the loss of the DigiDestined's ability to use their Digivices. He offers to return their Digivices if they can defeat him in battle.

The DigiDestined accept the challenge and engage in a heated battle against Myotismon. Eventually, they are able to overcome him and retrieve their Digivices. With their power restored, they are able to defeat Myotismon once and for all.

The episode ends with the DigiDestined returning to the real world, relieved to have saved the Digital World once again, and the knowledge that they will always have each other's backs.