New York City. 1897. Sara Howard has opened a pioneering private detective agency. She reunites with formidable alienist Dr. Laszlo Kreizler and New York Times journalist John Moore to find the kidnapped infant daughter of a Spanish dignitary.

Sara uncovers a clue at the Siegel Cooper Department Store that leads her into dangerous territory. Moore struggles to balance his personal and professional life as he investigates a link to New York's criminal underworld.

All is not what it seems at the Lying-In Hospital as Sara persuades a young nurse to disclose what happens behind closed doors. Kreizler is convinced that hypnosis might unlock the traumatic memories of Senora Linares.

The clock is ticking for the team to locate baby Ana. Sara worries about her young undercover detective Bitsy Sussman. William Randolph Hearst hosts a lavish ball celebrating his goddaughter Violet's engagement to Moore.

After the horrific murder of a Lying-In Hospital employee, the team are now hot on the heels of the murderer. Sara enlists the help of Joanna to tail their prime suspect. Sara, Kreizler and Moore try and put the pieces together.