The explosion was heard twenty miles away. It killed boatmen and wrecked the exotic villa of Lawrence Alma-Tadema, the fashionable St John's Wood artist. But what caused the 1874 Regents Park explosion? Fenian bombs? Sabotage by rival railways or other firms? Or was it something personal? And whose was the other body found in the canal? An artist's model? The missing King's Cross barmaid? Or another victim of the so-called Thames murderer? As he struggles to find the answers, Scotland Yard's Sergeant Ernest Best straddles the conflicting worlds of art, wealth and privilege and that of the poverty-stricken canal boatmen in an intriguing mystery that will change his life forever.