A very subtle distance in the relationship between the two high school students Tsumiki and Io leads to much confusion and misunderstandings: the very shy Tsumiki just cannot be honest about her feelings for Io, and he simply has no clue that she likes him. Unfortunately for Io all their friends — Hime, Mayoi, and Sakaki — understand the situation perfectly and simply cannot resist teasing Io at every opportunity.

[Source: AniDB]