The story begins with Shiori Niikura, a 24-year-old florist, who dies in a truck accident and is reincarnated as an Archeni, a half-human, half-spider monster. She awakens in a world where her mother and numerous sisters, all beautiful women with spider-like lower bodies, are engaged in a brutal survival of the fittest, consuming each other to become stronger. Shiori, with her human consciousness, cannot bring herself to eat her sisters and survives by hunting small animals.
After a month, her sisters have dwindled, and her mother has become a stunning beauty, while Shiori remains physically underdeveloped, appearing to be a 12-13 year old. Realizing her low level and the increasing danger from her stronger sisters, Shiori decides to escape the nest. She uses her Archeni silk-spinning ability to create clothing, including a practical dress and a backpack, and prepares to head towards human civilization. Her family, despite their predatory nature, allows her to leave, knowing she would eventually be consumed if she stayed.
Shiori, now in her Archeni form, travels through the forest, marveling at her enhanced physical abilities. She accesses her status screen, revealing her race, class as a "Dressmaker" tailor, and various skills like "Charm," "Thread," "Soft Thread," "Evasion Rate Up (Large)," "Escape Rate Up (Large)," and "Sensor Web." She discovers her "Predation" skill allows her to gain stats and skills by consuming magical creatures, explaining her sisters' strength from cannibalism. She also learns she can transform into a human form, though with reduced physical stats and some lost skills.
Emerging from the forest, Shiori encounters bandits who have captured Aize Foren, the daughter of a wealthy merchant. Shiori, using her silk abilities, incapacitates the bandits and rescues Aize. Impressed by Shiori's strength and skills, Aize offers her patronage and introduces her to her family in the city of Rihaku. Shiori, claiming her mother died and she needs work, is offered a position as a tailor. She opens her shop, "Archeni Dressmaking," which quickly gains popularity among adventurers due to the superior defensive properties of her Archeni silk clothing, especially after a demonstration of its durability against a bandit's sword.
Shiori's business flourishes, and she begins to acquire rare materials by hunting powerful monsters, including a Lesser Dragon and a Hydra, to create even more advanced gear. Her "Predation" skill allows her to grow incredibly strong, surpassing even her mother. She crafts high-quality armor and robes, attracting the attention of the Knight Commander, who orders custom pieces made from rare materials like True Dragon scales and Remia feathers. Shiori undertakes dangerous expeditions to acquire these materials, further increasing her power.
Her reputation grows, and she eventually encounters the Hero, Yusha Root, who is preparing to fight the Demon Lord. Shiori, initially amused, crafts powerful "Demon Lord's" themed equipment for him, which proves incredibly effective. The Hero's party, now equipped with her creations, finds their journey to the Demon Lord's castle surprisingly easy, with traps disabled and enemies weakened. They discover the Demon Lord has fled after being defeated by a "little girl" and subjected to humiliating rituals, leaving behind a note. The Hero, realizing Shiori's involvement, becomes her devoted fan.
Later, Shiori develops a revolutionary air cushion using her silk, which transforms transportation by allowing for faster, smoother journeys. This leads to overwhelming demand from merchants, the military, and the Horse Gear Guild, creating a chaotic situation at her shop. To fulfill the orders, Shiori reluctantly seeks help from her mother and sisters, who are more interested in her "affection" than in silk production. She manages to secure their cooperation by promising them custom clothing and narrowly avoids their more intimate advances.
Shiori also encounters various individuals and situations, including helping a young boy named Zel and his village by creating protective "Aracheni Sister" dolls, and later assisting a knight named Harn in dealing with Sirens who are luring ships to their doom. She uses her unique abilities and understanding of music to pacify the Sirens, discovering they were displaced by a powerful Kaiser Achelon. She also crafts a powerful "ear-cleaning" tool from a King Bamboo, which becomes a popular service at her shop.
The story concludes with Shiori's shop becoming a renowned establishment, catering to adventurers, nobles, and even royalty. She continues to expand her business, creating unique items and services, and her reputation as a skilled and powerful individual grows, hinting at future adventures and challenges.
