New York, late 19th century. In a decent boarding house on Astor Square, a murder occurred - one of the guests was strangled. Shortly before this tragedy, midwife Sarah Brandt found herself in the rooms - the owner of the establishment needed her services. To her amazement, she recognized the victim of the crime as a very young daughter of one of the richest families in New York, who lived in a boarding house under a false name. And then it turned out that the murdered woman was pregnant... Burning with indignation, Sarah decided to help in any way she could, police sergeant Frank Malloy, who was investigating this case. But he is shocked by her zeal - after all, women and detectives are incompatible...