The Tokyo Hero Project was a plan which was implemented two years ago, placing cosplaying heroes in each of the 23 wards to promote public order. But not many people knew that they actually possessed special powers and fought against the secret evil society Black Outsiders (BO) at night. Koutarou is a poor student who lives by himself. One night while he was making his way to a part-time job, he saw a fierce battle between a cosplayer and someone wearing a kigurumi. Due to the incident, he ended up missing his part-time opportunity and his friend Nagahiko suggested a new one for him. A young girl with a black manteau welcomed him: “How wonderful it is to have you here at the secret society BO group!”. From that day on, he battles against heroes while wearing a mascot character powered suit. Do your best, Koutarou!