In the Vermillion Bird Empire, women possess an innate potential for high-level immortal arts, granting them a position of immense power. However, they are required to wear restrictive ceremonial gowns for extended periods to prevent the dissipation of their magical energy. Men in this nation are denied the right to education and are excluded from holding significant positions; their sole responsibility is to care for the women who, due to their tightly bound existence, are unable to manage their own daily lives. Once a formidable and renowned general, she now lives in retirement, dedicating her time to nurturing her daughter. Subsequently, the Second Princess, who long held de facto command of the military and achieved remarkable feats, found herself under suspicion from the elder officials of the court. Faced with the turbulent undercurrents of the imperial court, the Second Princess, under the guise of a routine inspection tour, secretly sought out her former mentor, the retired Great General, to implore him for a method to overcome her predicament.

A detention day is an event where only female students spend the entire day in a state of restraint. Classes are held as usual. Restraint Day is a tradition at this high school, and is said to have begun shortly after the war. It is said to be an attempt to make children grow into strong women at heart by living their school life under restraints. The time is at the beginning of fall. There is no set date, and a day is usually chosen when the weather is just right for this period, which is neither too cold nor too hot. Therefore, the schedule is not announced in advance, but decided and informed on the day. The higher the degree of dress coverage, the higher the degree of bondage. [Upper half of the body bare: Hands handcuffed in front.] [Upper half of the body in underwear: Hands tightly bound behind the back. A gag ball is worn over the mouth.] [In uniform: Hands tightly bound behind the back. Wearing gag ball over mouth. Wearing leg irons. Wearing a collar.

Her arms were folded behind her back, wrapped tightly in a translucent leather holster with a pinkish sheen. The lacing at the holster's interface was tightened to the point of being extremely tight at each of the pull holes, making the leather tight against Iori's skin and outlining the curves of Iori's slender arms; several straps used to hold it in place buckled around her shoulders, neck, and waist, connecting to a single glove, making it impossible for Iori to get out of the leather's confines. Iori blushed, not daring to look up at Hanako, who could only see the roots of Iori's tiny ears, which had turned a fascinating shade of scarlet from the accelerated blood flow. Not only that, but Iori was now unable to use her hands to wipe away the juices that flowed from her mouth. Crystalline liquid dripped from the edge of the round rod that was stuck in Iori's small mouth, forming two thin silver wires

The eyepatch looks like thick metal that is impervious to light. The clothes that covered the neck down emitted a metallic luster. From the slender neck to the dimpled collarbones, bulging breasts_, slim waist, tight hips and skinny limbs, even the small indentation in the navel was visible. The hands were studded with thick metal handcuffs, attached with short metal rods, like a prisoner's wooden shackles. The feet were shackled, each ring of the chain as thick as a thumb and only slightly wider in length than the shoulders, so they could not run. Wide collars that strangled into the flesh were attached to the chains between the shackles and the fetters. Chastity belts were embedded in the waist. Triangular metal plates dangled from the corseted belt, covering only the hole in the front, and the chains at the apex were attached through the strands _between_ the strands to the back. The chains of the collar are held by him who walks in front of them