• Age: 12 to 18
• Grade: 7 to 12

Get steeped in suspense, romance, and high Victorian intrigue as Mary goes undercover at Buckingham Palace — and learns a startling secret at the Tower of London.

Queen Victoria has a little problem: there’s a petty thief at work in Buckingham Palace. Charged with discretion, the Agency puts quickwitted Mary Quinn on the case, where she must pose as a domestic while fending off the attentions of a feckless Prince of Wales. But when the prince witnesses the murder of one of his friends in an opium den, the potential for scandal looms large. And Mary faces an even more unsettling possibility: the accused killer, a Chinese sailor imprisoned in the Tower of London, shares a name with her long-lost father. Meanwhile, engineer James Easton, Mary’s onetime paramour, is at work shoring up the sewers beneath the palace, where an unexpected tunnel seems to be very much in use. Can Mary and James trust each other (and put their simmering feelings aside) long enough to solve the mystery and protect the Royal Family? Hoist on your waders for Mary’s most personal case yet, where the stakes couldn’t be higher — and she has everything to lose.

Y. S. LEE is an award-winning poet and novelist whose first young-adult novel, A Spy in the House, was nominated for an Agatha Award and won the inaugural John Spray Mystery Award. Ying won the 2022 Foster Poetry Prize, and she published her first chapbook, Exit Permit, in 2023. She lives in Kingston, Ontario, with her family, where she is also an organizer with Kingston WritersFest. Mrs. Nobody is Ying's debut picture book.

Y.S. Lee's profile page

Victorian England comes alive again with Y.S Lee’s third novel in THE AGENCY series. Lee has a terrific knack of combining intrigue, romance, and mystery with the strong female character, Mary Quinn... Girls of all ages will enjoy the fast pace, the twisting plot, and most of all, the romance that awaits them.
—VOYA

Lee, as ever, paints an evocative picture of London life... Mary makes for a bold heroine (sometimes too bold for her own good), and her fans will want to find out how it all ends.
—Booklist

The series offers young readers a spirited introduction to Victorian London.
—Toronto Star

Full of interesting twists and turns, this beautifully crafted story will delight readers who enjoy mysteries set in times gone by.
—Through the Looking Glass Children's Reviews

The Traitor in the Tunnel (The Agency, Book 3)