Note: This episode needs to be watched to be fully appreciated; theres a huge Animation Bump and the episode marks where the series starts to take a major turn.
Having just defeated Etemon, Taichi and Koromon are utterly flabbergasted to find themselves suddenly back in Japan in the real world; on top of that, everything has an extremely surreal feel to it, and feels alien to even Taichi. Even worse, Koromon is starting to attract attention from the human crowds everywhere.
Taichi recognizes himself as being in Odaiba, his hometown. Knowing this, he feels immensely relieved that they defeated Etemon and are now back in the real world. Taichi takes Koromon to where he lives, a large apartment complex, and wonders if his parents have been worrying about him — or, worse, if he' been out so long that his parents have forgotten about him or that some complete stranger now lives there (ignoring that there's a large plaque reading "Yagami" on the door).
Taichi enters to find his house deserted but recognizable, and enjoys having some cola from the fridge. Seeing the calendar on his fridge, he finds in shock that despite the potential weeks he spent in the other world, it's still August 1, 1999 in the real world. This does not help Taichi's uneasiness over where he is, and he wonders whether he's dreaming — or if the entire other world was a dream and that he'd been in the real world all along. Before he can ponder on this further, however, Koromon alerts him to a presence behind him —
— his younger sister, Hikari.
Hikari, bizarrely, seems to recognize Koromon before Taichi even introduces him, explaining it only with "Koromon is Koromon". While she's playful with Koromon, she's also quite listless, possibly as a result of having a cold. Their parents are out to visit their grandmother and she's fending for herself, but seems to not know about "the other world" at all. She asks Taichi why he's home from camp already, and suspects that Taichi went to "the world where Koromon is".
Hearing this, Taichi has the idea to call the other kids' families to see if they returned as well, but only gets confused responses from their parents. This does not help Taichi's constant mental struggle with whether he's dreaming, and which world is the dream. Deciding that they need food, Taichi makes omurice for himself, Koromon, and Hikari, having picked up some egg-cooking skills from his time in the other world. Hikari finds the eggs delicious but doesn't have much of an appetite, so she gives her portion to Koromon, who devours it.
While Koromon takes a needed potty break, Hikari tells Koromon about how her brother would always help her when she wet the bed by washing her underwear for her and taking the blame for her to their parents, calling him "really nice".
Taichi's relaxation is quickly interrupted by the morning news, reporting on the bizarre weather and showing a faint image of a giant Digimon in the area — which nobody seems to notice. Realizing that the Digimon are causing the weather, Taichi becomes alarmed, and Hikari reveals that she could always see the Digimon, but nobody would believe her. On top of this, they receive a staticky video message from Koushirou on their computer, and when Taichi explains that he's made it to the real world, Koushirou's broken-up message saying that Taichi "won't be returning". A completely alarmed Taichi concludes that both worlds are real, and his friends are trapped in the other world.
While they eat watermelon, Hikari asks Koromon if Taichi really has to leave, and offers for them to stay. Taichi himself makes this offer to Koromon after hearing his mom on the other end of a phone call, especially because there are still summer activities and homework he has to do, and almost throws his Digivice away before he's interrupted by a Tyrannomon emerging from the water outside. Hikari tries to stop him, but Taichi tells her to stay put and runs outside with Koromon.
More Digimon begin to appear and disappear outside, which normal people don't notice. Koromon concludes that Digimon don't belong in Taichi's world, and decides to return to the others. Hikari comes out to meet them despite Taichi's order for her to stay at home, and an Ogremon appears in the crowd, which gets a reaction out of Taichi's Digivice when Taichi resolves to fight with Koromon, and Koromon evolves to Agumon and drives Ogremon into a dimensional rift.
Agumon follows Ogremon into the dimensional rift in the sky, bidding farewell to Taichi and Hikari. Taichi tries to follow him... but is held back by the arm by none other than Hikari.
Taichi, knowing that he must follow Agumon, promises that he'll return soon, tells Hikari to get better, and rises into the sky as Hikari slowly loses her grip on Taichi. Taichi returns through the dimensional rift, leaving a very confused and sad Hikari behind.
The narration cuts in and reveals that soon, Hikari will set foot in the Digital World herself, and we see a Digivice on the table...
- Animation Bump: As stated, the animation for this episode was given a significant boost. Likely to make it clearer that the series is a sequel to the Digimon pilot movie.
- Breather Episode: This is the first episode after the Etemon arc and before the Myotismon arc, and it mostly shows Tai and Koromon relaxing back at home after their victory.
- But Now I Must Go: Tai hates to leave his sister behind but knows Agumon and the other still need his help and tearfully tells Hikari he'll return soon.
- Creepy Child: Hikari isn't necessarily creepy, but there's something distinctly uncanny about her listlessness and her recognition of Koromon. However, her attachment to Taichi and her expression upon seeing Taichi leave her again make her sympathetic and significantly tone down the odd factor.
- Invisible to Normals: The giant Digimon rampaging through the world and drastically changing the climate are simply invisible to most people — a few report seeing them on news reports, but this is dismissed as them just seeing things.
- Sequel Episode: To the Digimon pilot movie. It even reuses the same music and animation.
- Sequel Hook: Near the end of the ep, we're told Hikari will enter the digital world herself and we see a Digivice laying on a table in her apartment.