Gozen 3-ji no Muhouchitai

Story

Momoko, who dreams of becoming an illustrator, finds employment in an ultra fast-paced office that specializes in designing pachinko parlors!! With the office running a yazuka-like business and employing a designer, who has a habit of suddenly stripping in the middle of the night, Momoko believes that the company employees are a bit... no, definitely eccentric!! She continues pulling all-nighters, unable even to return home... And in the midst of cigarette-filled fumes, where women's authority takes a step back, she asks herself, "What am I doing here?"

Synopsis via AniList (English).