Daisaku and Minami suspect that a strange villa standing in the heart of the Japanese Alps is a secret base of BF Syndicate. They approach the house to get some proof, when men in the house notice them and look for them. When the two men get into danger, a mysterious man who calls himself Yanagida helps them and takes them into his hut. Although he isn't their enemy, he seems to have some grudge against the three men. During the fight it suddenly starts to snow. It is caused by Iceler, a huge icing monster of the syndicate. Daisaku calls Giant Robo, but the robot is frozen by Iceler's fluid and buried under the snow. Minami is arrested and Daisaku enters the house against Yanagida's advice to fulfill his duty as a Unicorn member.
