Detective Charles Lenox is called to Oxford. A young student is missing and his mother, Lady Annabelle, is frantic with worry. Charles visits Oxford and the boy's room searching for clues. Remnants left behind are very odd, including a dead cat. And what about the card with a notation of "September Society" with a strange pink and black marking on the back?

Charles Lenox, a Victorian gentleman, helps his lifelong friend Lady Jane determine who murdered one of her servants.

"It's 1876, and Charles Lenox, once London's leading private investigator, has just given up his seat in Parliament after six years, primed to return to his first love, detection. With high hopes he and three colleagues start a new detective agency, the first of its kind. But as the months pass, and he is the only detective who cannot find work, Lenox begins to question whether he can still play the game as he once did. Then comes a chance to redeem...

Visiting his uncle's estate in Somerset for what he hopes will be a quiet working vacation, politician and new father Charles Lenox investigates a series of seemingly small acts of vandalism only to uncover a sinister plot by an adversary who may be targeting someone Lenox loves.

Returning from a continental honeymoon with his wife, Lady Jane Grey, newly elected MP Charles Lenox is asked by his colleague, Ludovic Starling, to investigate the murder of his footman who was bludgeoned to death with a brick. Lenox gradually realizes that what seem to be the facts of the case may have been manipulated, and that an old friend may be implicated in the footman's death. Though a suspect is soon arrested, Lenox isn't convinced. Desperately...

"It's London in 1876, and the whole city is abuzz with the enigmatic disappearance of a famous foreign pianist. Lenox has an eye on the matter - as a partner in a now-thriving detective agency, he's a natural choice to investigate. Just when he's tempted to turn his focus to it entirely, however, his grieving brother asks him to come down to Sussex, and Lenox leaves the metropolis behind for the quieter country life of his boyhood. Or so he thinks....

Detective Charles Lenox agrees to help Lady Annabelle find her son, who has disappeared from Oxford University, and soon realizes the case is more complex than he thought when he uncovers a surprising link between the missing student and the school's September Society.