A boy who admires Bun Blue appears and asks to become his apprentice. However, Ishirou does not want any part of it, leaving the situation to Bun Black instead.

As ISA is making suspicious moves, Baisu Maimi, a co-worker of Shirabe, returns to Japan. Meanwhile, the Boonboomger are getting wiped clean.

Genba has a heart-to-heart with someone he least expects. The Boonboomger use a new invention to transform into a powered-up form to confront Mad Rex.

Genba is defeated by Dissrace and rescued by Sakito when they run into a mysterious man on the railway tracks.

A new powerful enemy has arrived, and Genba seems to have some history with him…

Shirabe is to explain the Boonboomgers to the head of ISA. Meanwhile, Taiya and the others have to fight a familiar Grumer. What’s more, something extraordinary happens…!? The 3rd LAP…

Taiya is seriously wounded after his fight with Mad Rex and Shirabe informs the team that the ISA decided to have the Boonboomgers disbanded and their equipment confiscated.

Taiya reveals his real intentions to form the Boonboomgers, which is to participate in the “Big Bang Grand Prix”, the biggest and most important race of the entire universe, while…

Mira goes out on her first solo delivery while a clock-themed Hashiriyan tries to stop everything that moves.

Mira Shifuto’s about to get married to a man she doesn’t want to when she’s suddenly whisked away by a deliveryman.

Ishiro still won’t acknowledge Mira as a Boonboomger as the team has to deliver classified documents to a foreign ambassador.