Ever since her husband, Thomas Brand, was murdered, his wife Sarah has worked as a midwife, all the while hoping to find whoever murdered her husband, but when she became friends with Frank Malloy, an Irish detective on the New York City police force, she knew he was different.
Unlike most of the police, who are merely uneducated thugs who will find a likely suspect for a crime and beat or intimidate a confession out of them, Malloy is an actual detective who relies on clues and suspects. After Sarah helps him on several cases, Frank agrees to look into the murder of her husband, which most other police wouldn't do without a hefty bribe, which is why the case was never solved in the first place.
This time, Frank finally has Sarah's father on his side. Sarah's parents are wealthy and fairly high up in New York society, but Sarah spurned their wealth to marry her former husband, who was a middle-class background, but spent his life helping the poor and indigent. Now, her father realizes that Sarah will never rest until her husband's murderer is found, and hires the Pinkerton's to help out Frank.
Frank learned that Thomas Brandt was investigating a mental condition called "Old Maid's Disease", where unmarried women become fixated on a man that is kind to them, to the point where they believe that the man loves them and is even having an affair with them.
Dr. Brandt had recieved referrals of cases from other doctors, some of whom had fallen prey to these women themselves. Frank finds a boy who was paid to lure Thomas Brandt to where he was killed, and he said the killer was a man with a silver cane, and that what he said made it clear that he blamed Thomas Brandt for what had happened to his daughter. The only question is, whose daughter, and which of the patients Thomas Brandt was investigating at the time of the murder did the man blame him for?
Frank investigates all the families, including one woman who has twice become violent, first waiting with a knife in the cellar of the home of her doctor that she was in love with, the second time actually slashing the wife of a minister she had fallen for. But Thomas Brandt wasn't the doctor she was in love with, although he did upset her when he questioned her about her love for the other doctor.
Along with the young woman above, he must also investigate the other women, some of whom have moved away from New York City because their families wished to escape the shame. But when Sarah's adopted daughter Maeve wishes to "help" with the investigation, but Frank refuses her, she runs away to do it on her own.
Later, she returns, only to be tapped by the Pinkertons to infiltrate the household of another "Old Maid's Disease" sufferer, this time as a nursemaid to the family's younger daughter. But when Maeve uncovers a secret someone will kill for, she must evade a killer as well as uncovering the true murderer of Doctor Thomas Brandt.
This book is the best so far of the "Murder by Gaslight" series. Victoria Thompson has come far as a writer, and the story was a series of twists and turns that really kept me guessing as to who the ultimate murderer would be. But she also managed a twist in the end that I didn't see coming, and which actually made me quite shocked.
Her true beauty as a writer is in her characters, and they are full of it... character, that is. Each character comes off as a real person, even the minor characters, like two nosy, gossipy sisters who keep their eyes on the doings of an entire neighborhood.
As well, this book is the end of a mystery which has plagued the series from the start, yet promises more to come with the epilogue. I am completely enamoured of this series, and this book, and it only added extra cachet that I have a friend in New York that actually *lives* on Bank Street.