Yen Press is releasing the manga in English, and it describes the story:
In the depths of a murky mansion lives a group of enigmatic nobles known as...the Shadow family. With no visible features to speak of, these mysterious aristocrats employ living dolls to act as their “faces.” Kate and Emilico are one such pair of mistress and servant, dwelling in their own little world and learning from each other bit by bit with every new day. But in a house of locked doors, living according to rules from no apparent source—how long can their blissfully peaceful existence truly last...?
The manga launched in Weekly Young Jump in September 2018. Shueisha published the manga's 17th compiled book volume on May 17. Yen Press published the sixth volume on March 19.
The manga inspired a television anime that premiered in Japan in April 2021. Funimation streamed the anime as it aired in Japan, and it also streamed an English dub. The anime's second season premiered in July 2022. Crunchyroll streamed the show as it aired in Japan.
Source: Weekly Young Jump issue 33