"My sister is beautiful, cheerful, bright, and family-oriented", but she is actually a mentally unstable girl. This is the story of the younger brother "Taichi" who is swung around by his older sister "Nanase Kurumi".
The main focus of the story is Asano, an employee who just can’t quit smoking, and Tabako-chan, who is the anthropomorphized smoke of a cigarette and whose clothes start to dissolve the closer you get to finishing your cigarette. She clings to your clothes like the smell of cold smoke. Aside from Tabako-chan, there is also the menthol cigarette character Menko-chan, and the Golden Bat, born in 1906, who are all anthropomorphized cigarettes that have turned into beautiful girls.
The manga tells the story of what Mayuri experiences during the final chapter of the visual novel, anime episode 23, and the lives of Mayuri, Okabe, Daru, Suzuha, and Luka in the year after Okabe's first failed attempt to save Kurisu in the 1.129848% β world line divergence.