In the Victorian era, the British Empire is bustling with the energy of the steam-powered industrial revolution. Following in the footsteps of his famous family of inventors, James Ray Steam enjoys his youth in Manchester helping at local factories and stealing components for his own creations. One day, he receives a package containing a strange ball with an attached valve from his grandfather, who has been working in the United States alongside Ray's father. However, it is not long before people from the O'Hara Foundation storm into his house demanding he hand it over. Confused and afraid, Ray attempts to flee to the home of his grandfather's colleague, Robert Stephenson, with pursuers hot on his trail. While Ray seeks to piece together the secret of the ball and discover the power it contains, it seems practically everyone in the British Empire is ready to seize it from him.

Command, control, and communication: the three pillars to successfully execute missions in modern military combat. They are also the source of inspiration behind Stella Women's Academy airsoft club, aptly named the C3 Club. Due to the club's nature, the members have trouble finding newcomers, but, as the school year starts, they hope to find their next sharpshooter among a new crop of students. Yura Yamato is a freshman at Stella; she sports an unassertive personality that makes it difficult to make friends. She soon discovers her absent roommate owns a massive collection of military memorabilia and movies, including a replica Desert Eagle. When one of the C3 Club's members catches Yura re-enacting an action movie, she drags her into the Club's airsoft practice match. Despite being on the losing side, Yura is unexpectedly drawn to the excitement of the game. Upon her return, Yura's roommate—Sonora Kashima—reveals herself to be the C3 Club's president and invites her to join. Now with Sonora by her side, one more exhilarating match convinces Yura to sign up. Thanks to her new teammates, Yura discovers a hidden side to herself and an unexpected love for airsoft. However, as her dedication to the game slowly takes over her life, Yura finds herself on the path of great change and success—one that may easily lead to self-destruction.

During Japan's Taisho Era (1912-1926), a scientist named Ayanokoji developed the Steel Angel - an artificial humanoid with superhuman physical abilities. While the Imperial Army wanted to use the Steel Angel as a new means of modern warfare, Ayanokoji wanted his creation to be a new step in the future of mankind. Thus, he defied orders from the Army and secretly made the Steel Angel codenamed Kurumi. Then one day, a young boy named Nakahito Kagura snuck into Ayanokoji's house as a dare by his friends and stumbled upon Kurumi's lifeless body. A sudden attack by the Imperial Army shook the house, causing Kurumi to fall on Nakahito. At that moment, their lips met, and Kurumi woke up from the kiss that started a miracle. (Source: ANN)

After successfully returning to Earth on the renovated Stratos 4, the four main characters are visited by the Comet Blasters Chizuru Kubo and Annette Kerry, who bring them a shocking video. Meanwhile, Orbital Station 7 is in serious trouble... This two-episode OVA comes between the first and second seasons. (Source: ANN, edited by Glenn Magus Harvey)