Number four in the Benjamin Franklin series (Benjamin Franklin and the Case of the Artful Murder, 1994, etc.) finds the inventor- statesman and Nick, his 13-year-old son, setting out on the two-day journey from London to Bath. Their carriage is shared with Dr. Woodridge, who hopes to set up practice in Bath; silent little F.J. Mossop, who hides a pistol beneath his oversized coat; and Mrs. Fanny Snow and her pretty, spirited niece, Emma Morland. Franklin has been invited to Bath by Arthur Brown, an expert on Roman history and artifacts. In his letter of invitation, Brown asked Franklin to guard Emma, who lives next door to him with her aunt and her uncle Edgar. Franklin is convinced that the letter had been opened and resealed but hasn't a clue as to why. Mid-journey the coach is waylaid by a highwayman who holds Emma hostage until help arrives with the dramatic appearance of handsome Lord Edmund Darly. Franklin is the target of a later attack--thwarted because of his own vigilance and his growing feeling that something's amiss. Arrival in Bath confirms his suspicions, as Emma is courted by Darly and taken round the city's baths, balls, walks, and shops by Darly's well-connected friend Mrs. Valentine. Nick wonders why Darly seems afraid of his surly manservant, Albert Noakes, and why their own aged neighbor, Isaac Hobhouse, is so unfriendly. Meantime, Emma acquires a second suitor--gambler Tom Bridger--while Arthur Brown yearns for her speechlessly. There are spurious identities galore, a murder, and a kidnapping before Franklin sorts it all out and effects a just-in-time rescue. A glowingly alive evocation of the era's Sin City, a nicely mystifying puzzle, and Nick's charming narration--all make for the best of this series so far.