A girl arrives at a military academy as a transfer student with no idea how to be human around other people, and the show makes her social paralysis funnier and more real than most romance anime manage. The first episode promises one kind of Gundam story; by episode three you realize the show is about something quieter and more dangerous: two girls learning to trust each other in a place built on lies. It breaks its own genre expectations without apology and never looks back.

In the year Ad Stella 122, corporations have expanded into space and built a vast economic system. Suletta Mercury leaves the remote planet Mercury at her mother's urging and enrolls at the Asticassia School of Technology, which is run by the Beneritt Group, the dominant force in the mobile suit industry. At the school, duels between students settle who is right, and the top duelist wins Miorine Rembran as a fiancée, a prize set by her father. When Guel Jeturk, the school's best pilot and Miorine's current fiancé, insists that she move in with him, Suletta objects, and he challenges her to a duel. Suletta wins, but she is then held on suspicion of piloting a banned GUND-ARM, or Gundam, and her win is thrown out. Miorine answers with a new duel carrying higher stakes: if Suletta loses, she is expelled and her treasured Gundam Aerial is destroyed.