MAT receives word of a monster sighting, so they disembark aboard the Arrows to fight it. Goh's ship is taken down by the four-legged, horned monster and immediately engages in battle with it as U-Jack. Proving to be a formidable opponent, Ultraman ultimately loses the fight. His color timer expires and he disappears. As a result, Goh ends up in the hospital with numerous injuries. While Goh is out of commission, the other MAT members believe the beast thrives on atomic power. Goh's friend Sakata helps him train to strengthen his injured leg so that he can have a return match with the monster, Kingsaurus III.
第一原子力発電所付近に、怪獣キングザウルス三世が出現した。郷はウルトラマンに変身するが、キングザウルス三世にはウルトラマンの必殺技が通じなかった。怪獣が発生させるバリヤーを飛び越えるキック技を会得するしか、倒す術はない。郷は坂田の協力を経て、過酷な特訓を始める。
