As the asteroid Nemesis approaches Earth, the Earth Defense Force rushes to complete construction of the missiles "Proton One" and "Proton Two." However, just before completion, the giant monster Dorgler and the giant combat robot Helgaiser MkII suddenly appear, threatening the success of the Proton Project. Earth Defense Force officer Minami Yuki transforms into her true self—the giant heroine Alphalady—and confronts the two enemies. During battle, a mysterious ultrasonic wave strikes, instantly reversing the tide of combat. Despite her initial advantage, she is ultimately overwhelmed and defeated... [BAD END]