From Decadence:

Spring of 1921 in the Taisho era, Ichijo Maria had lost her parents and entrusted herself to a friend's family. She leaves the house when the father became physical with her. Maria wanders the town and collapses in front of her old house. She is saved by a young doctor called Toudou Sei. There, she learns the house is currently being used as a dorm by the doctors of Imperial Maria Hospital. Remembering her fathers words, "I was tricked by Toudou!" she works there as a maid under a fake alias in order to reach the truth...