Kakeru, a former elite runner at high school, is chased for stealing food. He is saved by a Kansei University student Haiji, who is also a runner. Haiji persuades Kakeru to live in the old apartment 'Chikuseisou' where he plans to team up with fellow residents to enter Hakone Ekiden Marathon, one of the most prominent university races in Japan. Kakeru soon finds out that all of the residents except for Haiji and himself are complete novices.

In the fictional Tokyo suburb of Mahoro, Keisuke Tada (Eita) works as a "benriya" - a general problem solver for hire.

One day in January, former classmate Haruhiko Gyoten (Ryuhei Matsuda) appears unannounced. Back in their schooldays Haruhiko was a quiet person who rarely talked. Now, Haruhiko is talkative. Both men are over 30 years old and divorced. Without giving an explanation, Haruhiko suddenly asks to spend the night at Keisuke's home. Keisuke turns down Haruhiko, but Haruhiko is persistant and finally Keisuke allows him to sleep over for one night. What Keisuke is unaware of is that Haruhiko plans to stay for more than one night. Eventually, Keisuke accepts Haruhiko as his assistant and they become involved in various cases involving an assortment of people from different walks of life.

From Aerandria Scans:

Kogure-sou is a crumbling old apartment building of just six rooms where four people live. On the first floor are the owner, a very old man who wants to have sex before he dies, and a girl in university who pines in a sad and complicated love. On the second floor are a salary man who finds meaning to his life in spying on the university girl below him, and Mayu whose boyfriend disappeared three years ago. Also involved are the florist from the nearby shop who worries over her husband's infidelity and Mine who is still troubled by a crime committed a long time ago. What all of them strive for is love, but they all find nothing but pain and bitter disappointments. Do they realize that what heals them is actually the run-down little apartment building and the real human warmth that they share with each other?