Dangerous chain letters are beginning to circulate. Kiyoshiro erased a suspicious email (chain letter) received from a professor he knew. Suddenly, a large amount of small Zassoumon appeared and began biting him. At the same time, a similar email was sent from Kiyoshiro to Ruli and her friends, who had come to the Cafe Aqua. As soon as they were deleted, a large amount of Zassoumon appeared from their smart phones.
Zassoumon grow huge and become powerful when they drink liquid. These Digimon are appearing one after another from smart phones and PCs seeking water and rampaging. They bite people to steal their moisture. Since she looks so much like a collection of water molecules, Jellymon feels very threatened.
The boys at Kiyoshiro's dorm are blaming him for sending the chain emails, and he wants to restore his reputation. The kids race to Professor Bokomon to see if he knows anything about it. He believes that deleting the email triggers a virus. Kiyoshiro calculates that at the rate it is multiplying, it will soon take over Japan.
For the time being, Kiyoshiro developed a field with a lake in a pseudo-digital world. Along with Hiro and Ruli, he tries to lure Zassoumon near this lake. Unfortunately, the kids struggle with the ever-growing and enormous Zassoumon. Turns out that when they get hurt, they stick to each other to survive!
Not wanting to lose his champions (candy) if the World ends, Gammamon evolved into Wezengammamon. He is able to take out a lot of Zassoumon with the cannons on the front of his head, but they continue to get larger. Just when Wezengammamon is about to finish the whole lot, an elderly Zassoumon appears. He says that it was all his fault, and they're all his clones. He got lonely when coming to this World. He says he will take all the Zassoumon with him and not trouble them again. However, the way his eye squint makes him appear to be a force to be reckoned with later in the series.