Nagisa Miyoshi and Saho Miyoshi are sisters and very close to each other. Younger sister Nagisa Miyoshi leaves her hometown of Hiroshima and begins to live with her older sister Saho Miyoshi, who has already moved to Tokyo. Saho Miyoshi works as a wardrobe stylist. Nagisa Miyoshi gets a job at company which her sister Saho introduced her to. There, Nagisa Miyoshi meets Yosuke Asakura, who is her first love from her high school days. Her feelings for him are rekindled, but she learns that Yosuke Asakura is engaged to her older sister.
Adapted from the manga series “Sister” (シスター) written by Ayapan (あやぱん) and illustrated by Shijimi Tsubasa (蜆ツバサ).