This world has gone through many Dusks, and is slowly nearing its end. Within this world, in the western reaches of the "Land of Dusk," there was a nation that prospered thanks to its use of alchemy. There, in order to survive the eventual arrival of the "Dusk End," the people devoted their efforts to rediscover and recreate lost alchemic technologies. Rediscovered technology from the past era was gathered in the alchemy research city known as "Central," where research was conducted on how to halt the advance of the twilight. One of the heroes is a young man who researched alchemy in Central, the other a girl living in a small town on the frontier. This girl's name is Escha. In the process of using her knowledge of ancient alchemy to help others, she was assigned to the Development Department. The young man's name is Logy. Having learned the newest alchemic techniques in Central, he requested a transfer to this understaffed town to make use of his abilities, and meets Escha when he is assigned to the Development Department as well. The two make a promise to use their alchemy together, and bring success to the Development Department.

Shou Zama is an ordinary 18-year-old from Tokyo who finds himself summoned to the medieval fantasy world of Byston Well. Upon arrival, he is put into service under the ambitious lord Drake Luft, who seeks to greatly expand his power. Those like Shou who come from "Upper Earth" possess strong aura power and are ordered to pilot "Aura Battlers," insectoid mecha designed by a man named Shot Weapon, who also came from Upper Earth. However, Shou's alliances quickly change when he meets Marvel Frozen, a young woman who has decided to rebel against Drake's political agenda. As he realizes the lord's true intentions, the boy chooses to join the fight against Drake and team up with Neal Given, who leads the resistance movement. The resistance isn't alone—Riml, daughter of their enemy and Neal's secret love, aids their efforts, hoping to escape from her father's clutches. As Shou finds himself fighting alongside his new comrades, they put their lives on the line to prevent the villainous Drake from taking over Byston Well before it's too late.

In the final years of the Bakumatsu, wandering mercenary Yojiro Akizuki travels the length and breadth of Japan. And while he employs his sword in the usual fashion, he also uses it to help him locate supernatural items which he pursues with single-minded determination, often with bloody results. In the course of his quest, he crosses paths with a traveling theater group whose members have their own dark agenda. Is it a chance meeting or the result of some, as yet, undiscovered conspiracy?

107 years ago, the Moon was destroyed in a massive cataclysm that shattered Earth's former satellite into 81 quintillion tons of orbital debris. However, thanks to super-science, the Earth itself was saved and today no one really thinks much about that century-past disaster. Which is why when teenage Haruka Amami auditions for something called the Idolmaster Project, she THINKS she's trying out to be a singing idol. Instead, Haruka finds herself at a secret school run by the Mondenkind Agency, living with a group of other girls who have also been selected as candidates to pilot an iDOL - an advanced robot specifically designed to intercept falling chunks of moon rock. Except, the people who run the Mondenkind Agency aren't exactly knights in shining armor. And then there's the question of whether the iDOLs are really JUST robots. Because from almost the first moment, Haruka starts to feel emotions resonating from within the iDOL called Imber.