As Takato and Henry arrive at
Okinawa for their summer trip, they part ways as Takato stays with his cousin Kai and his grandfather, while Henry visits the underwater ruins offshore. Meanwhile, Rika, who is staying home in
Tokyo, fights a Pteramon at an
oil plant; she and Renamon become suspicious of Pteramon's motives for attacking. The next morning, Takato, Kai, and Guilmon save a girl named Minami from Tylomon. Minami explains to Takato that she was being chased by many Digimon because her laptop carries the original prototype V-Pet, which was modeled after her late puppy, Mei. Much later, Scorpiomon and Divermon try to capture Minami. Seasarmon appears from the laptop screen and saves her, but Mantaraymon escapes with Minami. Meanwhile, V-Pets are causing technical viruses around the globe, and taking over entire computer systems. Takato and the others go to the island where Minami is held captive. They find Minami's father, who reveals that the prototype V-Pet carries a vaccine program, and Tameshiro, the head of the V-Pet manufacturing company, is revealed to be a Digimon named Mephistomon that sent the Digimon to capture Minami. As Seasarmon tries to attack Mephistomon, he is bested and devolves to Labramon, resembling Mei. Henry and Rika arrive via Omnimon's help, who reveals that it has been hunting for Mephistomon from the beginning. Takato and the others fight and seemingly delete Mephistomon, while Minami tearfully acknowledging a dying Labramon as "Mei" activates the vaccine, which cures the computer systems over the world. However, Mephistomon evolves into Gulfmon and overpowers the partner Digimon. Calumon enables the partner Digimon to digivolve to Ultimate-level and defeat Gulfmon, setting everything back to normal. ==Voice cast==