Legendary rap group The Dirty Dawg could have taken Japan by storm, but then they broke up. Now each member fights in one of the four rival groups. Battles for turf are fought with rap and the Hypnosis Mic, a microphone that can affect the human spirit.
Just after the second division battle ends, a string of ordinary citizens go on the rampage. On top of that, there's a hostage situation at a hotel in Ikebukuro. The objective: revenge against the Buster Bros!!! Ichiro, Jiro, and Saburo dash to the scene!
The Katen-gumi is attacked. When Samatoki Aohitsugi, Jyuto Iruma, and Rio Mason Busujima arrive to help, they meet self-proclaimed "legendary gambler" Chuji Furoito. Meanwhile, MAD TRIGGER CREW has its hands full with the civilian rampages.
Samatoki recognizes TBH's dancers. Bad things will happen if they aren't stopped, so MAD TRIGGER CREW joins forces with Ichiro Yamada, Ramuda Amemura, and Jakurai Jinguji. Elsewhere, bad things are happening around Nagoya Division's Bad Ass Temple.
A huge man named Ondoriya challenges Sasara Nurude, Rosho Tsutsujimori, and Rei Amayado—Osaka Division's Dotsuitare Honpo—to a rap battle. An accident during the battle causes Ondoriya to lose his memory. Sasara and Rosho try to help him get it back!
Jakurai goes to Nagoya to look for clues about TBH and runs into Hifumi and Doppo. Hifumi is working at the Nagoya branch of the host club. When they hear that club patrons have info on TBH, Jakurai, Ichiro, Kuko, and the others go help out at the club.
MAD TRIGGER CREW and Fling Posse learn that there are clues about TBH in Osaka. They ask Dotsuitare Honpo for help and start gathering information. A crew of three imitating Fling Posse appears. Something about seeing a copy of himself irritates Ramuda.
Ichiro and the others head to Osaka Bay to dismantle the bombs at the theme park where TBH announced they're holding an Underground Division Rap Battle.
MAD TRIGGER CREW and Dotsuitare Honpo arrive in a new area and fall into TBH's trap; the two teams are shown footage of Samatoki's younger sister, Rosho's student and Rio's former commanding officer -- only one can be saved.
TBH dancers Kiaro and Skuro appear before Ichiro and Kuko. Ichiro says that he's sure they're people he used to know, but the dancers don't remember it. Meanwhile, when Matenro and Fling Posse arrive in their arena, they're ambushed by assassins.
TBH appears again before Ichiro and the others. They say that if they're beaten in a rap battle, they'll spill everything they know. Ichiro, Samatoki, Ramuda, Jakurai, Kuko, and Sasara accept the challenge. After the battle, the mastermind is revealed.
Everyone who fell into Kaibyakumon's trap divide into groups and head out via three helicopters. Ichiro and the others agree to help suppress the rioters in Tokyo. The six members in the third helicopter head to Shibuya to confront Chiaro.
The six leaders arrive in Chuuoku where the special forces have started rioting due to the influence of Kaibyakumon's drones. The second helicopter lands in Shinjuku where they start looking for the drones' control server, but they fall into Scuro's trap.
The six leaders head to the former site of Beginning Gate where they find Kaibyakumon waiting for them. Kaibyakumon transforms into a monster using hundreds of drones and overwhelms the six leaders with a rap overflowing with rage and despair.
