The Custom House Murders by Ashley Gardner

Captain Lacey encounters an old army friend just returned from Antigua, who is being accused of smuggling and possibly murder. Lacey decides to help the man, whom he considers honorable, to clear his name.

Meanwhile James Denis has given Lacey a task, to deliver a mysterious package to a man with an office near the Custom House on the bank of the Thames. Lacey, who has been drawn into danger delivering items for Denis before, opens the package beforehand to find a single chess piece, a white queen.

The piece tells Lacey nothing, but he soon realizes it plays deeply into Denis’s ongoing battle for control of London’s underworld.