An alien invader from an extremely cold world, like others before him, Grost came to Earth to take over. He quickly made a home base out of a construction area and took control of the workers. When a small child discovered the being and his captured slaves, they tried to stop the child, but he eventually escaped and sent out the word of the invasion. Luckily for the invader, no one believed the words of the child, not even ZAT. The child came back the next day, but now equipped to stop the invasion scheme. Armed with hot items such as coals and even a burning red stick, he quickly made the enslaved people flee. Once in the heart of the building, the child was surrounded. On cue, ZAT had decided to investigate the story, and found the child trying to fend off the alien's slaves. Once the fight got out of hand, Grost leaped out of the building, his towering form standing above the city. Kotaro didn't hesitate and transformed himself into Ultraman Taro, and the battle quickly began.The alien's ice mist began to spread around the area, turning buildings to ice and freezing an entire lake. The hero fell, his timer flashing and beeping. ZAT's support quickly came as they fired beams of burning energy onto the monsters back, melting the spikes the protruded. The alien turned and shrieked as his ice mist forced the pilots to jump out with parachutes and the planes crash on the ground. This gave Taro enough time to use the bracelet given to him by the Ultra Mother. The bracelet melted the ice covering the battle field, and Taro regained his strength. The being of power downed the invader with a fury of kicks and punches before using another one of his attacks to cause the being to explode into thousands of pieces.