Hiro's friend, Kotaro, is acting very strange. He is washing his face and saying "filthy" repeatedly. He even tried to wash Hiro!? Gammamon notices Kotaro is different, but not in appearance.
Later that day, Hiro meets with Ruli. She says that Mika is acting the same way. Hiro sees for himself when Mika and Aoi arrive, and Mika immediately starts washing the table...saying filthy as she does. Again, Gammamon says Mika is different.
Hiro gets a frantic call from Kiyoshiro, but when he meets up with him, he too is different.
When the two return to the dorm, students are piling up their belongings, because they believe they are...(you guessed it) filthy. Not far off, Ruli uses her digivice and finds that her friends and the students have been turned into wooden dolls.
In the Digital World, Ruli is captured by a female shrine digimon. The digimon removes her impurities, which changes Ruli to a wooden doll. Angoramon was unable to do anything. He quickly finds Hiro.
On Earth, Hiro is the last impurity in the city. Angoramon recognizes the digimon that appeared as Kuzuhamon. When she gets her hands on Hiro, Gammamon evolves to Canoweissmon!
Canoweissmon battles with Kuzuhamon, but is overtaken by her Uraizuna. Again she grabs Hiro and begins to strip him of his impurities. She plans a ritual to cleanse all impurities.
Hiro and Canoweissmon's strong emotions connect resulting in the Mega Evolution of Siriusmon. Hiro shouts Breaquasar! That attack stops Kuzuhamon. She mentions that someone sent the Digimon to this World.
Kuzuhamon calls off the ritual, and everyone returned to normal with no memories of what happened to them.