The title of the sixth book, published in February 2012, is "From the Deep of the Dark". While appearing as guest of honour at the 2010 Forum Fantastico, Portugal's national science fiction convention, Hunt described his sixth book as primarily a spy mystery. It features Dick Tull, an officer of the State Protection Board close to retirement, the consulting detectives Jethro Daunt and Boxiron, and Commodore Jared Black. The characters are investigating the theft of the Jackelian royal sceptre and a series of strange murders and bloodless corpses in the capital, Middlesteel. Thief Charlotte Shades is asked by two mysterious men to steal King Jude's Sceptre from the Parliament vaults. Daunt and Boxiron know there is more to the two men than meets the eye and, with the rescued thief, escape in an ancient submarine captained by Commodore Jethro Black. They encounter resistance from strange underwater races, but human, steam-man, seanore and gillneck must band together to save the kingdom from danger.