Digimon Fusion

It is a year since Taiki Kudō's adventure in the Digital World as he forms the “Xros Heart” basketball team together with Yū Amano, who became his junior at his school, and Tagiru Akashi. However, on his way home from game, Taiki sees a monstrous shadow within a space fluctuation before being confronted by three children. The leader of the trio recognizes Taiki and his potential but tells him not to meddle in their affairs before leaving. The next day after school, Tagiru hears a voice begging to be saved, and after seeing a spacial distortion, Tagiru gets dragged right into it and ends up in a Digital World like dimension called the DigiQuartz, where time flows differently to the real world. Tagiru sees the source of the voice, Gumdramon bring attacked by a MetalTyranomon until the three children arrive and fight it with their Digimon, but it escapes from them. After being told they are Digimon Hunters, Tagiru wants to be one too as he is told to get a X Loader first.

After returning to the Real World, finding out that Digimon can be Reloaded outside of DigiQuartz, Tagiru learns of Taiki and Yū's past experience with the Digimon a year before. Inspired to be at Taiki's level, Tagiru returns to DigiQuartz to begin a new Hunt. The two encounter a mysterious shadow behind the abductions of students: Sagomon. Sagomon overwhelms Gumdramon before he and Tagiru are saved by one of the three children, Ryōma Mogami. As this occurred, going to the alley were Tagiru got his Xros Loader, Taiki meets the Old Clock Store Owner and his Digimon Clockmon. The Owner proceeds to warn Taiki not to interfere with the Hunts due to expertise having an effect that would upset the balance of the "game". Though not intending to take part, Taiki promises to interfere if any one gets hurt in the cross fire. Nothing that Taiki has a strong will like Tagiru, the Old Clockmaker leaves, but not before giving Taiki the Hunter's Rulebook, which Tagiru forgot to get.

The members of the school's robotics club are frustrated because they keep failing to build a robot good enough to take part in the upcoming competition when they approached by Xros Heart's old friend, Puppetmon, who offers them a chance to take part in a greater project. The next day, while told to deliver a notice to the absent Tokio, Tagiru learns from Taiki that all other members of the robotics club are also absent from school, and fearing it to be Digimon related, he and Yū accompany him to Tokio's house, just to find him working on some machinery. Figuring that Tokio is deceiving his mother in thinking he is going to school to stay home, Xros Heart witnesses Tokio entering into the DigiQuartz through his computer. By following him there, they learn that Tokio and the other missing children have been building a GigaBreakdramon under Puppetmon's orders. Taiki and Shoutmon confront Puppetmon who seems to not remember them at all and launches GigaBreakdramon against them.

Tagiru's classmate Miho Sudo has been 1st place Honor Student since Elementary, stresses out on improving her grades when she is at 8th place. Miho's desire for the top 7 students to disappear attracts the attention of a Digimon who offers to make it a reality for her. Later, feeling jealous of Tagiru and Gumdramon, Yū meets Miho. Soon after, news of the two top students in their grade, Mishima and Takahashi, being attacked and looking malnourished drives everyone in school in an uproar. Only Miho had no reaction to the event as Yū follows her while Tagiru enters the Digi Quartz and finds the school covered by a vine looking plant whose tendrils are wrapped around Mishima and Takahashi while draining them. Losing the vines' source, a flustered Tagiru and Gumdramon are encountered by Ren as he tells them that can not defeat vine Digimon unless they find its true form. Deciding to help for his own benefit, Ren has Dracmon bite into the vine to expose the Digimon.

At a cute store called the Fancy Shop Dream, Airu Suzuki, along with her Digimon Opossumon, capture a bunch of other Digimon. Finding that all of them are "no good", Airu leaves the Digimon to her teammates. Still feeling down about not being able to reunite with Damemon, Cutemon appears in front of Yū to cheer him up but ends up being targeted by Airu, who wants to add him to her cute Digimon collection. While Yū returns home, with Tagiru and Gumdramon tagging along, Cutemon spots a bunch of pictures of Nene, who has since become an idol in Hong Kong. After falling asleep from their meal, Cutemon, Tagiru, and Gumdramon awake to find Yū gone. Finding Yū at the park where he and Damemon first met, Tagiru, Gumdramon, and Cutemon make just in time as Airu transports Yū to the DigiQuartz. Trying to force Yū to hand over Cutemon, Airu nearly succeeds, until her DigiXros of Opossumon and Candlemon allows them to escape.

The Xros Heart boys join the school's kendo club for the regional tournament and after winning a match, they find that they are being observed by Musashi Kenzaki, a student from a rival school. Later, Musashi ends up in the DigiQuartz and meets Kotemon who takes him as his pupil. Some time later, a mysterious figure starts challenging members from adult kendo clubs throughout the city and beats them to the point of shredding up their clothes. Tagiru and the others figure out that this incident could be Digimon related and investigate by themselves until they find that the mysterious attacker is actually Musashi. Tagiru challenges Musashi for a match and he sees a second blade appearing on his other hand for an instant to block his attack. Musashi flees and Kotemon appears, offering himself to train Tagiru asking him to help bring Musashi to stop following the dark path he is taking.