Oga Itsuki, an office worker, is an ordinary adult salaryman. He
wakes up in the morning, goes to work, works, occasionally works overtime, goes home, eats, takes a bath, sleeps, and goes back to work... Every day is filled with work, but he doesn't get much out of it. It's a repetitive, ordinary life that most working people probably lead.

His boss leisurely tells him,
"Just change. From now on, even if just a little."

If he does that, he might see his days differently than before. Learning things he didn't know, meeting people he didn't know -
Itsuki wants to change his daily life, so he starts taking action to do so... but that very night, he ends up having a physical relationship with a woman he's met for the first time. It's a development that would never have happened before. The daily life of a working adult changes little by little with many encounters.

(Source: Pink Pineapple)