Kotetsu is put on paid vacation and decides to go home to visit his daughter, Kaede, purchasing a strange plushie known as a Mad Bear along the way. Meanwhile, Barnaby appears to have found the criminal responsible for his parents' murder, Jake Martinez. On his way home, Kotetsu encounters a terrorist bombing on a bridge, deciding to handle it alone so that Barnaby can investigate Jake. He soon finds the attackers are a group of mechs being piloted by living Mad Bears, with more bombings taking around the city. With the heroes overwhelmed, Baranaby decides to postpone his prison visit to assist Kotetsu. Just then, the culprits reveal themselves to be Ouroboros, putting the entire island at hostage and demanding the release of Jake in exchange.