When PI Carlotta Carlyle is hired to go underground it's more than a figure of speech; she's investigating rumored theft and corruption on the big dig of the title, Boston's multibillion dollar tunnel project. She's also involved in another case, that of a missing woman whose friend, wealthy Brahmin Dana Endicott, knows that even if Victoria left her job tending bar or her other job caring for animals at a local dog-grooming company without giving notice, she would never have abandoned her beloved dog, who's been left behind at Endicott's Back Bay brownstone. Then a workman who alerted authorities that things were disappearing from the dig site dies in a fall that might be an industrial accident but on closer investigation, begins to look like murder. It takes the determined Carlyle a few more beats before she links her two cases with the big Patriot's Day celebration planned at Faneuil Hall on the anniversary of the Waco massacre, but by the time she has, she's located the missing woman and a kidnapped teenager, foiled the bad guys, and managed to bed an undercover FBI agent--attagirl, Carlotta! A lively and engaging heroine in a tidy mystery whose fast-paced narrative slows but doesn't stop for the details about Boston's ambitious, overdue, and overbudget urban renewal project.