The traitor in the tunnel / Lee, Y. S

When Mary Quinn is ordered to work undercover after a petty thief steals from Buckingham Palace, she receives attention from a prince, wonders at a murder suspect's shared name with her father, and struggles with her feelings for James Easton.

The Agency, the all-female detective unit, assigns quick-witted Mary Quinn to the case. Posing as a palace maid and fending off the attentions of the Prince of Wales are challenging enough, but when the prince witnesses a murder, Mary's case becomes antything but petty. Engineer and former flame James Easton has an assignment in the sewers, where someone is making illicit use of the tunnels. Mary will need James's help if she's going to catch a thief, solve a murder and avert disaster.

Mary Quinn is assigned to the Queen's case and sets out to identify a petty thief at work in Buckingham Palace and finds herself fending off the advances of a feckless prince, but a larger scandal looms when the prince witnesses the murder of a friend in an opium den.