The vanishing thief / Kate Parker.

"Georgia Fenchurch appears to be an unassuming antiquarian bookseller in Victorian London, but the life she leads is as exciting as any adventure novel. For Georgia is a member of the Archivist Society, a secret association of private investigators led by the mysterious Sir Broderick. When a frantic woman comes to Georgia claiming that her neighbor, Nicholas Drake, has been abducted by the notorious Duke of Blackford, Georgia and the Archivist Society agree to take the case. But Drake is no innocent--he is a thief who has been blackmailing many of the leading members of London society. To find Drake and discover who is behind his abduction, Georgia and her beautiful assistant, Emma, will have to leave the cozy confines of their bookshop and infiltrate the inner circles of the upper crust--with the help of the dashing but dubious Duke of Blackford himself. But the missing thief and his abductor are not the only ones to elude Georgia Fenchurch. When she spies the man who killed her parents years ago, she vows to bring him to justice once and for all...at any cost"--