They are in the Digital World, Island Zone
Shoutmon: This is... Our homes.
Gumdramon: And it's the Island Zone.
Damemon: Let's go find him.
They went to the Secret Place
Lucemon: This world has been connected.
They saw the City disappeared
Whisper: What was that, Whis?!
Lucemon: Tied to the darkness... Soon to be completely eclipsed, There is so very much to learn, You understand so little, A meaningless effort, One who knows nothing can understand nothing.
They saw Lucemon as Psychemon
Lucemon: Take a look at this tiny place, To the heart seeking freedom this World is a prison surrounded by Data. And so this digimon sought out to escape from his prison with his friends, They sought a way to cross over into other worlds. And they opened their heart to darkness.
Psychemon has turned into Lucemon
Lucemon: Don’t bother. Your voice can no longer reach him where he is. His heart belongs again to darkness. All worlds begin in darkness, and all so end. The heart is no different, Darkness sprouts within it, it grows, consumes it. Such is its nature. In the end, every heart returns to the darkness whence it came.
They jump back
Lucemon: You see, darkness is the heart’s true essence.
Shoutmon: That’s not true! The heart may be weak. And sometimes it may even give in.
Gumdramon: But we've learned that deep down, there’s a light that never goes out!
Lucemon rised up
Lucemon: So, you have come this far and still you understand nothing. Every light must fade, every heart return to darkness!
He Summon his guardian and they fight him after that he's retreating from them and the Digital World is falling apart. Shoutmon, Gumdramon and Damemon, went to stop Lucemon and then their Friends has been block by a Force Field, So Shoutmon, Gumdramon and Damemon will have to fight Lucemon on their own after that Lucemon has been defeated