Vesper is a secret agency fighting an army of alien invaders by using super-powerful battle androids. Mahoro is Vesper's most powerful battle android and has won many battles, but she has little operating time left and soon will cease to function. However, if she lays down her arms and conserves her remaining power, the time she has left can be prolonged to just over a year. Mahoro is given an opportunity to live the remaining time she has as a normal human. She chooses to live as a maid for Suguru, a phenomenally messy middle school student who lives by himself after his family passed away. (Source: ANN)

As the relationship between Mahoro, Suguru and his classmates develops further, another android girl enters their lives and becomes attached to Mahoro. All the while, the number of days before Mahoro is to shut down decreases steadily. (Source: ANN)

The story takes place during a conflict between the Krakozhia Dukedom and the Grania Republic. In the midst of the fighting, a savior appears to the Krakozhia Dukedom, and it is a high school student named Yano Souhei. Two female soldiers, First Lieutenant Ruto and Second Lieutenant Haruka, appear in tanks to intrude on Souhei's everyday life, followed by the enemy soldier Shachirofu, all of whom use firearms without hesitation at his house. (Source: ANN)

It is year 0079 of the Universal Century. Mankind has moved to space, living in colony clusters known as "Sides." One of these Sides declares itself the "Principality of Zeon" and declares war on the Earth Federation, the governmental body currently ruling Earth. Using powerful humanoid robots known as "mobile suits," Zeon quickly gains the upper hand. Nine months into the conflict, the Earth Federation has developed its own powerful mobile suit called the Gundam. When Zeon launches an attack on the colony holding the Gundam, a 15-year-old civilian named Amuro Ray suddenly finds himself thrown into a conflict that will take him all across Earth and space, pitting him against the enemy's ace pilot, Char Aznable. [Written by MAL Rewrite]