This EXCELLENT summary was written by "Akino Ame"...Thank you!!
Images prepared by me (Julie).
After the mountain's collapse, Takuya, Koji, and Tommy find themselves falling down a large earthen tunnel only to land on.giant bouncy balls? As surprising as it is, the trio fell right into a giant ball pit:
Takuya: "Whoa, is this a big playground? And if it is, what needs a playground this big?"
Tommy: "We're gonna find out, aren't we?"
Takuya: *depressed* "Of course."
Meanwhile, beneath the island they're flying on, in some king of blimp thing, a group of Agumon seemingly made of black Legos vows to go to the Human World and get revenge on the children there.
As the three make their way through this odd toy land, trying to find Zoe and J.P., they encounter a flying robot toy that Tommy just has to follow. Takuya takes chase, having promised to protect him, while Koji follows soon after, wondering which one of them is worse. They come across a pile of toys, including a toy car set where Tommy begins playing.
Koji gets increasingly more ticked off the longer they stay there, and snaps at Takuya when he finds the robot and begins fooling around with it. Embarrassed, Takuya shouts at Tommy to stop playing, while the boy mutters about them being worse than his parents as they walk away. But he's still determined to have fun, and while they're wondering if they can find the others at the Forest Terminal, he shows off a balloon and a toy pig he found. Again, they tell him that they can't stick around playing, and he looks depressed. Takuya tells him not to cry, but he gets angry and starts sulking. Takuya comments that he feels bad, but Koji tells him not to, that "The little baby has to grow up sometime." This results in yet another argument between the two. Once you've seen one, you've pretty much seen them all.
In an attempt to get them both to shut up, Tommy discovers a small train that can transport them (if you've ever seen the Sailor Moon episode "Nightmare in Dream Land," it's the same type of train Serena, Raye, and Darien were on), much to his delight and Koji's chagrin. He and Takuya have quite a bit of fun tormenting Koji by chanting "Koji's playing with toys!" The next thing they find is a giant yellow teddy bear walking around.
Anyone who thinks this sounds like "Togemon in Toy Town," raise your hand. Hmm, that many, huh?
Yeah, it's Monzaemon, of course. He throws Takuya to the ground, declaring himself champion wrestler of the world. When he wants to try a rematch, Takuya and Koji take Tommy and run for their lives from the crazy bear, taking refuge in a Viking ship. But, knowing their luck, this is the last place on Earth where they're safe. The ship is actually a pendulum ride, and wouldn't you know it? Tommy gets motion sickness. But aside from making him nearly throw up on Koji, the ride does give Takuya the chance to notice that they're on a floating island before it finally stops and they're let off. Takuya offers to give him a piggy back ride since he's still sick from the ride, but Koji tells him not to - if they're attacked while Tommy's riding, Takuya would be too slow to get away. Tommy sadly says that he'll walk since they really don't have a choice in the matter, and Takuya points out a building that looks like cake, suggesting that they should see who lives in it. Hansel and Gretel, anyone?
One of the black Lego Agumon notices the children, and turns to Monzaemon, warping his evolution into a dark-colored Ultimate. He is to capture them so they can use them as bargaining tools for when they arrive in the Human World.
The building was a candy store, and Tommy runs directly to the cotton candy, grabbing one for himself, and one for each of his friends. Takuya digs in, but Koji refuses on the grounds that they still need to get to the Forest Terminal, resulting in another argument over whether or not Takuya is a good leader. Koji's worried that the other Legendary Warriors will be enemies like Grumblemon was (ooh, clairvoyant, isn't he?), but Takuya doesn't want to talk about this in front of Tommy. Koji again insists that they have to treat him more grown up, but the argument really doesn't do anything other than make Tommy think that Koji hates him. They nearly argue again as they walk out of the candy store, but the black Monzaemon (revealed as WaruMonzaemon) kidnaps Tommy! They run after him, but are stopped cold by his Heartbreak Attack. For about two minutes, they're extremely depressed and crying (at least Takuya is anyway), but it fades away quickly, and they're forced to start looking for yet another missing comrade. Takuya's distraught, and begins confiding his fears to Koji:
Takuya: "This really reminds me of the time I lost my little brother at the amusement park. I've never been so worried in my life until now."
Koji: "I know. Little kids are always getting in the way."
Takuya: "That's not what I meant! Man, you must be the most selfish kid in the whole world! Two worlds! We have a responsibility to take care of Tommy because he's younger than us! Don't you take care of your own brothers and sisters?"
Koji: "I don't have any. Happy now?"
Takuya: "Oh."
Koji: "See, I don't know anything about having brothers." (Note: Funny that he only mentions brothers and not sisters. Foreshadowing, perhaps?)
Takuya: "Well, why don't you just imagine that Tommy is your little brother? And think what it would be like for a little kid to be alone and afraid. Imagine that you could keep him from feeling that way."
That resolved, Koji runs off in search of Tommy, with Takuya right behind him. Tommy, meanwhile, is crying in a lavender castle in the background when all of a sudden he has to inform his captor that he needs a potty break. Odd little kid.
Takuya and Koji are pointed to the castle by the flying robot. Takuya keeps commenting on the color, for some reason, and when they try to enter, the black Agumon (ShadowToyAgumon) knock them off the drawbridge and into the moat, where a creature called Pandamon rescues them. Miscellaneous dub comment of the day: he talks in the style of Adam West's Batman, if you've ever seen it on Nick at Nite. And yes, he calls his hideout "the Panda Cave." He explains the ShadowToyAgumon's plot and how they were corrupted by Cherubimon as he walks them to a secret entrance to the castle. Again, the two humans are attacked.
Making a long story short, they try to fight the enemy, but the ShadowToyAgumon keep taking on different forms: first a tank, and then two giant robots (that oddly look like Megadeuces from Big O). Lobomon and Agunimon trick them into knocking each other out before scanning the Fractal Code, devolving, and running inside the castle. They hear Tommy's shouts for someone to stop hitting him, but when they break down the door, they find him playing videogames with his captor, returned to a regular Monzaemon. It turns out he managed to solve the problem while they were gone and was playing games the whole time. Somehow reminds me of the whole thing with Puppetmon wanting to play with T.K. Needless to say, neither Takuya nor Koji was very happy about having wasted all this time trying to help him when he was fine the whole time. In apology, the newly reformed ToyAgumon agree to fly them back down to find their friends.
