Mikey, an upbeat seventh-grader who can't resist helping people in trouble, encounters a Digimon named Shoutmon, who brings him and his friends to the Digital World in order to save it from the Bagra Empire. Once they realize they are no match for MadLeomon, they are joined by a handful of others to help them succeed in their mission.

Shoutmon holds a banquet in a desperate attempt to keep Mikey from leaving the Digital World. The evil Bagra Army attacks and Shoutmon is at a disadvantage, until Mikey helps him combine with his Digi-friends using Digi-Fusion.

Mikey, Angie and Jeremy have become allies with Shoutmon and his fellow Digimon. Still trying to defeat the Bagra Empire, they meet Christopher and Nene, two other humans living in the digital world. Will Christopher and Nene help Mikey? Or do they have plans of their own?

With proof that controlling a Code Crown makes you the ruler of that zone, Mikey and Team Fusion Heart go in search for the Island Zone's Code Crown in order to protect it from the Bagra Forces.

Evil Neptunemon learns the Code Crown is inside Whamon's belly, so he drops a mixture of DigiByte snacks and bombs from the air to weaken the gigantic Digimon. But Shoutmon wards off the bombs with no regard for his own safety.

When Mikey's team is surrounded by Seadramons on the island, Christopher shows up and offers to help in exchange for the Digi-Memory Card.