Tamotsu finds a series of new hobbies, and being who he is, he runs off to pursue them. Meanwhile, Arisa, Niwaka and Matome go on patrol without him, and receive a type of attention that they did not expect.

Tamotsu needs a new PC, and he decided to build one from scratch. He's trying to create something totally one-of-a-kind, and gets more than what he expected.

Arisa helps Tamotsu rediscover a card game that he stopped playing a few years ago. Meanwhile, another Bugged One conspiracy is at play, causing chaos within the Akihabara vigilante groups.

The Akihabara Festival, a major government-backed event, is about to begin. As everyone works hard to prepare, behind the scenes, an unknown group conducts unspeakably evil deeds to ruin the fun.