Passionate athlete Mikey Kudo tries to help a strange creature in need only to be transported with Angie Hinomoto and Jeremy Tsurgi to a place known as the Digital World. There they meet the strange creature Shoutmon and more creatures who are known as Digimon.
Mikey stands next to Shoutmon, Ballistamon and Dorulumon, leading the Fusion Fighters army into battle against the Bagra Army. Holding up a red device, a Fusion Loader, Mikey shouts "DigiFuse!" In response, the three Digimon become Shoutmon X4 and display immense power with the Star Sword by wiping out waves of the Bagra Army. Greymon jumps out to challenge Shoutmon X4 and, as the two collide, Mikey jerks forward, revealing it was just a dream. Meanwhile Angie Hinomoto, Mikey's childhood friend, is looking for him and calls Mikey's mother only to find out he has gone out for a sporting event without her. After being momentarily sidetracked, Angie figures out where Mikey is and rushes off with supplies.
At school Mikey finishes up a basketball game which his team wins thanks to his skills and great teamwork. Angie barely makes it in time to save an exhausted Mikey from hitting the floor. While Angie reprimands Mikey for being so careless, Jeremy Tsurgi appears, announcing a challenge to his "eternal rival" Mikey who beat him at a kendo match. While Angie and Jeremy fight, Mikey hears a voice lamenting its impending death. Mikey hurries to find the source of the voice to help while Angie and Jeremy chase after him.
Electronics begin to go haywire as reality shifts around them. Mikey saves Angie and Jeremy from danger with the help of the voice, and, rushing into an alleyway, Mikey discovers a small digital version of a hurt Shoutmon. A light appears revealing a Fusion Loader while a voice asks Mikey if he wants to protect Shoutmon. Saying yes, a light envelops the three kids as Mikey reaches for the device.
Waking up from their fall, Mikey, Jeremy, and Angie find themselves sitting in strange place that is filled with lush green grass. From the Fusion Loader on Mikey's belt, they hear Shoutmon's voice. Before they can figure out where they are, they encounter an army of Mammothmon and their leader MadLeomon who attacks them. Ballistamon appears from underground and counter's MadLeomon's attack, saving the bewildered kids. Shoutmon "reloads" out of the Fusion Loader and attacks the enemy with the help of Ballistamon, Starmon and some Pickmon. Mikey uses his Fusion Loader to digifuse Shoutmon and Ballistamon into an incomplete Shoutmon X4. Unable to hold the form, the two change back while MadLeomon absorbs his Digimon soldiers.
Once more Mikey uses DigiFuse to Shoutmon and the Starmon and Pickmonz into the Shoutmon + Star Sword. With the Star Sword, Shoutmon defeats MadLeomon, causing him to revert back into his original state and release his absorbed soldiers. Before he can attack again, MadLeomon is forcefully withdrawn with his injured forces by Tactimon, who saw the failure along with Laylamon, Blastmon, and Reapmon.
Celebrating the victory, Shoutmon informs Mikey that he is a General since he can use DigiFuse. Shoutmon adds that with the power of Mikey he has a chance to become king of the Digital World. When Mikey and the others remark they don't know what Digimon are, Shoutmon tells them they are in the Digital World, earning a reaction of surprise and disbelief. Nearby, Nene Amano and Christopher Aonuma observe the group.
Shoutmon Type: Small Dragon Special Moves Fiery Fastball Rock and Roller
Monitamon: "Shoutmon. His attacks include 'Fiery Fastball' and 'Rock and Roller', where he shouts so loud that his opponents are obliterated! What a silly attack! Imagine just shouting all the time; who would want to do that?" Shoutmon: "That's why they call me Shoutmon, you annoying hunk of junk!"
Shoutmon Type: Small Dragon Special Moves Rock Damashī Soul Crusher Rowdy Rocker
Monitamon: "Shoutmon. Its technique is to strike at the opponent with the shout of its soul (Soul Crusher). Let me try that, too. I'm hungry! Gimme food!" Shoutmon: "That's the scream of your soul?!"
As MadLeomon's army is pulled back by Tactimon, there are unconscious Rhinomon in the background, even though no Rhinomon were actually shown in the battle between the Fusion Fighters and MadLeomon's army.
In the English dub, Dorulumon's head is present on Shoutmon X2 (Incomplete X4)'s shoulder due to the scene being taken from another episode.
When Angie leaps to put a pillow underneath Mikey when he collapses, the kanji on her bag after the word "Taiki", is originally blue but turns to red for that scene and then shifts back to blue.
Mikey narrates the dream while the original doesn't have narration.
Troopmon's guns are recolored to bright orange in Mikey's dream.
The English dub has Mikey mention he has had the same dream many times before.
While in the original version Mikey was only a substitute player for the basketball club, in the English dub he's a regular member of the team.
The Japanese text was removed from the background posters in the basketball scene.
Lillymon's dress is painted as green from the waist up.
In Shoutmon and Ballistamon's DigiFuse sequence, the text on Shoutmon's cards is translated. Additionally, the shot of Ballistamon is erased.
The DigiFuse montage used is also taken from later episodes which use a blue background.
Laylamon's robes are edited to completely cover her breasts.
While in the original Reapmon doesn't make any sound, in the English dub he says "Hmm".
The Data File is extended to have Monitamon explain what the skit is.
The shadowed Digimon who support the Fusion Fighters in Mikey's dream sequence are representatives of the previous seasons of Digimon, and most appear later on as DigiCards: