Dawn * Slave 2 ~Aka no Setsuna Shiro no Toki~

The stage is Manchukuo-era Qiqihar in the 1930s. The protagonist, Kamuriki Shigeaki, is ordered by his foster father, Hiroto, to train a former Russian noblewoman Olga and her daughter Tatiana. Though he has handled the training of women many times before, he begins to develop unfamiliar feelings toward this pair. Interwoven with interactions involving the maid Rosetta and the cook Rui Rui, Shigeaki carries out their training over three months.

[Translated from the official site]