Ojisan to Neko to Shoujo

It is the Taisho period. A straight-laced man named Shougo works as a teacher for an all girls school, and lives with his black cat named Kuroi-san. Then one day, his nephew brings him a tight-lipped servant who doesn't talk. Is this beginning of a curious, and slightly warm life of a man, a cat, and a girl?

(Source: LoreScans)