Kikka Tsumugu (28 years old) lives alone on the 2nd floor of an apartment building. Kikka, who works as a "wasai" (traditional Japanese clothing manufacturer) at home, is a job given by Mashimo, her ex-boyfriend from high school. One day Kikka was selected to be a board member of the apartment complex lives at and met with a man named Hirara...!? Mashimo lives 200 meters away from Kikka's house and Hirara lives 200m above. The vertical and horizontal romance triangle has begun!

Note: Vol.3, 4, 6, 7, and 8 include the spin-off prequel "Tonari no Binetsu" as extra chapters.