Iedechu no Imouto desu ga, Baka na Aniki ni Hogo saremashita.

is a Japanese light novel series written by Sasayama Plus, with illustrations by Roki. The series began publication on April 10, 2021 by ASCII Media Works under their Dengeki Bunko publishing imprint.

Synopsis
I never intended to return to this town. While being shaken by the car heading to the airfield, Ryuji felt his heart fluttering with indescribable anxiety.

Ryuji, a graduate student who abandoned his hometown when he entered school. However, during the summer vacation, he returned to his hometown to supervise the laboratory-owned experimental airfield.

"--It's been a long time, fucking aniki."

What I was waiting for was my half-sister Juri, who had become a bad boy in the town. For Ryuji, it was the trauma he wanted to erase. Ryuji will live together with Juri, who is running away from home, at the airfield.

This is a younger sister of a bad elementary school student and an older brother who is returning home. A summer story about the reunion and rebirth of separated brothers and sisters.