Lupin is the main character in this series which takes place in Italy and San Marino. Reflecting its setting, the anime debuted in Italy before it aired in Japan. Lupin III fans will note that the titular thief now dons a blue coat, following his earlier appearances in green (first series and some OVAs), red (the second series as well as most films and television specials) and pink (third series).

In its expansion west to gain resources, the Europan Imperial Alliance invades the neutral Principality of Gallia, seeking to take control of its vast Ragnite deposits. Their strategic advantage, technological superiority, and military might make opposition nonexistent, so they steamroll through the border of the sleepy principality with ease. As Imperial forces run through his quiet hometown, Welkin Gunther and his younger sister Isara jump into action, banding with the leader of the local militia to push the occupational forces out of the village. Quickly retreating to the Gallian capital, they are organized into a unit with the remnants of the militia, tasked with assisting in repelling the Imperial presence from the country. Though unfamiliar with war, the newly formed Squad Seven must defend their country from annexation. But as the battle rages on through the streets of Gallia, ancient secrets will bring the team closer than they'd ever anticipated.

The story follows the school life of the three girls, Yuzuko, Yukari, and Yui, who join their high school's Data Processing Club. The odd friendship between the three make for wacky humor in even the most mundane of events.

It began in 1945, at the end of the Pacific War. Alien invaders filled the earth's Skies, and mankind was forced to confront an unprecedented threat. For the first time in human history, people of all cultures came together under one banner. This war has now been raging for over fifty years. Countless lives have been lost, and the Japanese military is now forced to rely on young people such as Atsushi Hayami and his high school class, also known as Unit 5121. This new generation fearlessly struggles on with the aid of the HWT humanoid combat machines and the devastating PBE bomb. (Source: Media Blasters)