Buckingham Palace, back in the day

The third book in the adventures of Victorian spy Mary Quinn amps up the camp

The stakes are high as the Agency series moves to the very top. The Traitor in the Tunnel sees Mary go undercover as a maid in Buckingham Palace.

Pilfering from the palace. A high-society murder in an opium den. Unwanted attentions from the Prince of Wales. A long-lost father, previously thought dead. A prisoner in the Tower of London. Oh my!

The Particulars

Historical Setting: 1860 London

Appearances by Historical Personalities: Queen Victoria, the Prince of Wales (later Edward VII)

Historical Events Covered: None, although the after-effects of the Second Opium War play a role

Timely Dialogue: “Then I saw their clothes: toffs.”

Toff: This was a derogatory term for the rich/nobility, particularly of the snobby variety. I wish we still used a term like this.

The Best Thing I Learned: A major plot in the book turns on the use of guncotton as an explosive (Guncotton, treason and plot!) As Mary says, these were “sheets of cotton impregnated with nitric acid. They’re highly unstable.”


Princess Caraboo

For a while, guncotton saw use as an explosive, but was eventually superseded by other materials that could be handled more safely. It eventually saw a second life for use in film stock.

Which Historical Personality Is This Book? Princess Caraboo was an infamous 19th century trickster. She posed as an exotic princess and was the toast of London’s high society, before being found out. She was still a bit of a folk hero, because people had a good laugh at the expense of the gullible upper class. Similarly, The Traitor in the Tunnel exposed the foibles of Britain’s nobility, was not what I expected, left me a little disappointed at the end, but created immense fun in the process.

The Review

Initially investigating thefts from palace collections at the behest of her royally-engaged bosses at the Agency, Mary gets entangled in a scandal involving the 19-year-old Prince of Wales. He witnessed the murder of an upper class ne’er-do-well in an opium den. The accused is Chinese and might actually be Mary’s father, previously presumed dead. On top of that, Mary stumbles on mysterious goings on in the sewers below the palace. This brings her into a collision course with her favourite engineer and foil, James Easton.

Combining plucky spy escapades with Downton Abbey-style melodramatic high-society scandals fit right in with this book series. However, The Traitor in the Tunnel felt like too much of a good thing and didn’t quite work for me as a sum of its parts. It’s still a rollicking good read. But I couldn’t help feeling a slight let down from the heights of the previous installment.

I don’t mind the outrageous coincidences. Each book in this series has been built on that. The author is well aware, offering this winking exchange:

THE TRAITOR IN THE TUNNEL, YS LEE, BOOK COVER, HISTORICAL FICTION, YOUNG ADULT, MYSTERY“It’s preposterous, isn’t it? Three coincidental meetings – it beggars belief.”


“I’d never believe it in a novel.”

The Traitor in the Tunnel is a wild ride that’s not supposed to be taken too seriously. I thought the previous two books navigated this line beautifully. This one leans a bit too much in the direction of unrealistic. When Queen Victoria becomes embroiled in the case directly, it felt like reading the historical fiction equivalent of Elton John’s Kingsman cameo (a bit much, but still awesome!):

These are the quibbles of a fan with high expectations of this series. The Traitor in the Tunnel is ultimately a fun read and does important work to set up the finale, which is outstanding and will be a subject for a future review.


An opium den in London’s East End


  • Strong chemistry between the two leads continues
  • Anti-Chinese fervour generated by the Opium Wars is an overlooked aspect of history that gets its due here
  • Great window on the “upstairs downstairs” operations of the Victorian upper class (hands up, Downton Abbey fans!)


  • The plotline of Mary’s family reunion and her main investigation don’t mesh seamlessly
  • One plot resolves itself too easily based on one man’s sudden change of heart

Now, on to the finale!

Final Rating:

★★★★ (of out 5)