The Agency: The Traitor in the Tunnel

The third book in the action-packed YA mystery series set in Victorian London, about Mary Quinn, a teenage investigator from a secret ladies' detective agency, perfect for fans of The Agency for Scandal and A Grave Inheritance.

Queen Victoria has a little problem: a series of petty thefts from Buckingham Palace. She calls the Agency for help, and they put Mary Quinn on the case. Going undercover as a domestic servant, Mary’s assignment seems simple enough.

But the simple assignment turns deadly when one of the Prince of Wales’s irresponsible young friends is murdered in scandalous circumstances and the story, if it became public, would disgrace the young prince.

Meanwhile, James Easton’s engineering firm wins a contract to repair some sewers beneath Buckingham Palace. Trouble is, there’s a tunnel that’s not on the plans.
These overlapping puzzles offer a perfect opportunity for James and Mary to work together again. If they can still trust one another...

Read all the thrilling books in The Agency series!

A Spy in the House
The Body in the Tower
The Traitor in the Tunnel
Rivals in the City