A special chapter featuring Robin Mask.
Robin Mask is known to keep a secret notebook, which contains all of the Justice Chojin secrets and weaknesses, and it is for this reason that he - and the book - are stolen away by an Evil Chojin named Boo-Ton. The other Idol Chojin chase after them, where they defeat Boo-Ton and save the unconscious Robin from harm.
Robin is known to keep a special notebook. 
In this notebook, he writes all about the Justice Chojin and their techniques, so that - over time - he can use his observations to help them improve. He takes his notebook to his office, where he writes notes about the chojin, but an Evil Chojin breaks through the wall and kidnaps him, as well as taking his notebook in the process. 
The other chojin notice the commotion, as the Evil Chojin says that they should meet him at Weak Point Star. Kinnikuman, Warsman, Brocken Jr, Wolfman, and Ramenman go to the place in space as commanded. The Evil Chojin is revealed to be Boo-Ton. Robin has been held up on a crucifix, where he is seemingly unconscious. 
Boo-Ton uses a canon of fake fists to attack the Justice Chojin at the same time, and he aims for their weak spots based upon the notebook. Brocken attacks Boo-Ton and take over the canon, but Boo-Ton is too large and the fake fists do no damage to his form. A beam of light emits from Robin Mask's helmet, which he uses to show them Boo-Ton's weak-spots. Boo-Ton surrenders, at which point the Justice Chojin use a Chojin Southern Cross against him. Boo-Ton is defeated by Friendship Power and dies at the scene of the attack. The Justice Chojin take Robin Mask home. 
Due to Kinnikuman losing at rock-paper-scissors, he must carry Robin Mask.