The euphoric homeostasis our protagonist Akiha enjoys while eating her breakfast is shattered when she has explained to her Kazane's marriage volition. Nami's derisive remark and Kazane having created several designs for the wedding gown prompts Akiha to recruit Imoko into her plans to vote with her feet. Galvanized by the prospect of an amplified allowance, Nami gives chase and tries to scare capitulation into Akiha only to find that Imoko has already steered for the space port where Akiha finds that she cannot board the transport due to not having her student card, a minor but unexpected setback that stops the agoraphobic Nami in her tracks. Imoko and Akiha drive to the school with two of Akiha's classmates, one of which secures an escape pod for Akiha which she and Imoko avail after school only to be caught in the midst of a gravity quake, a gravity quake caused by the brain colony Leopard phasing in from hyperspace. Ahika exploring around on Leopard before meeting the AI entity face-to-face sets the stage for a frenzied Othello sequence that introduces Itsuki Kannagi (who tries to arrest both Akiha and Leopard), the QT-Arms Starsylph (which Akiha uses to arrest Leopard's ballistic plummet with Itsuki's guidance), and Honoka Kawai (who seems to have been awaiting Akiha's arrival along with Akiha's other siblings Takane and Sakura.
In the year 311 of the Orbital Calendar, humanity has migrated to countless colony clusters in space. A space colony girl named Akiha Shishidou encounters a malevolent artificial intelligence named Leopard that has been installed on a colony.
