To save the Earth from alien invaders and their giant monsters, Dr. Kishida does what any passionate mad scientist would do: he builds a giant robot—ARIEL—the ultimate feminine combat machine.
Unfortunately, his granddaughters refuse to pilot it. They've got more important things to do than becoming teenage superheroes. Besides, how can anyone study for college entrance exams while getting beaten up in battle?
Meanwhile, the invaders are struggling too. Their reports described Earth as a perfect target: lush, peaceful, and relatively undefended. In theory, the planet should have surrendered long ago. Instead, the war has reached a standstill, the dreaded Accounting Department is warning of serious cost overruns, and the head of the home office has arrived from Galactic Headquarters to personally oversee operations. Is Headquarters planning to unleash The Audit, or do they have something even more evil in mind?
The fate of the world hangs on two people: Aya Kishida, one of the doctor's granddaughters, who may have to give up prep school to pilot the mighty (and lovely) ARIEL, and Saber Starblast, a mysterious alien who may be able to defeat the invaders once and for all...