Two sisters, with ten years separating them. Once close, they grew distant with time. As the younger sister enters high school, their relationship once again begins to change. This time in an unusual direction. (Source: MangaDex)

Souiu Toshigoro ni Nacchatta Toshi no Sa Shimai is a web manga released on the author's Twitter account since October 14, 2018, and published in print by Kadokawa since March 23, 2020.