Ore ni Kanojo ga Dekite kara Imouto-tachi no Yousu ga Okashii! | 俺に彼女ができてから妹たちの様子がおかしい！？

Parents are lost by an accident, protagonist Amari Yuuta who lives harmoniously with three younger sisters while working as patissier. She in the same office recently can do and the smooth sailing exactly... With contrary to expectations, younger sisters appearances are strange somehow. Dangerous appearance that worries to the doing places of eyes and excessive body touch have increased.

[I must firmly educate younger sisters as an elder brother...]

Though Yuuta that thinks about these kind of things, younger sisters acts become intenser, every day of younger sisters wielding the elder brother as a man starts.