Act of Vengeance by @Rosenspitze is a 1920’s murder mystery set in Germany with a single working woman P.I. who’s also taking care of her best friends’ daughter. She’s trying to crack the case on what happened to her friends as well as the shady dealings in her city. Similar to Miss Fisher’s Murder Mysteries! I highly recommend it if you like the '20s '30s vibes.
Edit: Oops! She already commented!