A quiet high school boy named Wakana Gojo has a secret passion that he has kept hidden for years. Following in the footsteps of his grandfather, a master craftsman of traditional Japanese Hina dolls, Wakana dreams of becoming a kashirashi, an artisan who sculpts the intricate heads of these ceremonial dolls. His single-minded dedication to this old-fashioned craft, however, comes from a place of isolation. A painful memory from childhood, when a friend called his hobby weird, has made him a social loner who fears rejection and struggles to connect with his peers. He spends most of his time in the home economics room, perfecting his sewing skills, believing that his interests place him in a world completely opposite to that of his trendy classmates.

One of those classmates is Marin Kitagawa, a vibrant, beautiful, and popular gyaru who seems to live a life of effortless glamour, surrounded by friends and the latest trends. From Wakana's perspective, she might as well be from another planet. But when Marin discovers him diligently working on a doll costume after school, she doesn't react with disgust. Instead, she is captivated. To Wakana's shock, this girl from the "other world" is a passionate otaku who loves adult video games and anime, and she has a secret of her own: she desperately wants to cosplay as her favorite characters but has absolutely no skill in sewing or making costumes.

Marin, brimming with enthusiasm, immediately enlists the reluctant Wakana as her partner, convinced that his craftsmanship is the key to bringing her dream cosplays to life. Though terrified of the social implications and the monumental task ahead, Wakana is slowly drawn in by her pure, unfiltered joy and passion for her hobby. He agrees to take on the challenge, and as he throws himself into the intricate work of making Marin’s costumes, he discovers a new sense of purpose and confidence. Their collaboration takes them on a journey through the world of cosplay, from taking meticulous body measurements and shopping for fabrics to attending conventions and navigating the complex unspoken rules of the community.

Their success attracts the attention of other cosplayers, including the talented and petite Sajuna Inui, known as "Juju," a cosplayer who specializes in magical girl characters, and her younger sister, the tall and shy photographer Shinju. Through these new relationships, both Wakana and Marin grow. Wakana slowly emerges from his shell, learning to stand up for himself and finding friends who appreciate his skills, while Marin’s feelings evolve from simple gratitude into a deep romantic affection for the boy who makes her dreams a reality, even as he remains oblivious to her advances. Together, this unlikely pair learns that passion for a hobby can bridge any gap, turning a world of isolation into one of connection, creativity, and love.