200m Saki no Netsu

Tsumugu Kikka (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!

(Source: Shueisha, translated)