Ken creates the Dark Spiral, a new version of his Dark Rings, to be able to control ultimate-level Digimon. Conflicted, Wormmon, Ken's Digimon partner, frees Agumon and Ken becomes furious that Wormmon released Agumon and condemns of having a weak Digimon like Wormmon as his partner. However, as Agumon reunites with Tai, Ken recaptures him with his new Dark Spiral and makes him Dark Digivolve into a virus version of MetalGreymon and attack the DigiDestined.