Due to unavoidable circumstances, Haruomi is freeloading at his relatives', the Orifushi sisters', house. Since that day, his common everyday life has come to a screeching halt.

The eldest sister is the gentle and maternal Natsumi. The second is Akina, a bright and cheerful girl for whom a smile is well-suited. The youngest sister is the bratty Mafuyu.

The curtain rises on Haruomi's new life in the company of these three beautiful sisters.