On his way home from drinking his sorrows away after being rejected by his crush, 26 year old salaryman Yoshida finds a high school girl named Sayu sitting on the side of the road and ends up letting her stay at his place overnight. Not having the heart to put the runaway out on the streets, Yoshida allows her to stay at his place... And so began the awkward, irritable, and slightly heartwarming relationship between a runaway high school girl and a salaryman living together.

Kakeru, a former elite runner at high school, is chased for stealing food. He is saved by 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.