SPOILERS! RUN AWAY or Hubbard will stab stab stab you
Ursula Kern (don't you just love these names) used to be someone else, but after being the co-respondent/attempted rape victim of the husband in a high profile divorce case -- she was working as a paid companion to the wife, who was more or less setting her up for this role -- she changed her name and started a secretarial/typewriting agency for women (historical romance novel, Victorian London). Now one of her friends and employees has supposedly suicided, but left behind odd things for Ursula to find that lead her to believe it may have been murder. Ursula attempts to take a break from her own current assignment cataloging artifacts found by a gentleman-archaeologist, Slater Roxton and asks for advice from him on the way out the door. Roxton decides to help her out on the case since he cannot dissuade her from investigating despite the risk (so, basically the usual plot). Roxton's backstory has some mystery martial arts and time stuck on an island after nearly being killed as an ancient temple self-destructed around him. He has put together a tile labyrinth in his basement. His father is dead. His mother (dad's mistress) is alive, as are his father's second wife and his step-siblings. Roxton is managing the money for the heirs, so he's got a lot of attention from the press.
Unsurprisingly, Ursula's identity is uncovered by none other than Gilbert Otford, late and later again of the Flying Intelligencer, so he actually gets some on page time (his articles appear in other Quick novels set in the same time and place). Obvs, the friend _was_ murdered and there's a complex, trans-atlantic drug, blackmailing and prostitution scheme that has to be dismantled. If you read JAK/Quick, a lot of this is familiar material (right down to the unemployed theater people working as domestics in Roxton's household, just like Desdemona's theater family in a JAK novel). If this is the kind of thing you like, well, here it is. If you find this all somewhat confusing, just move along.