The scene is the aftermath of the Enlightenment, marred by a series of macabre murders, Shepherd’s novel the perfect blend of political sophistication and human greed. Moving between two time frames—1812 London and 1769 Tahiti (Otaheite)—what is begun on a pristine island comes home to roost on English soil. A ship, the Solander, commissioned by Sir Joseph Banks, president of The Royal Society, returns to port filled with exotic specimens garnered from Otaheite and meant for the Royal Gardens at Kew. Long a believer in “a great project, allying the discoveries and theories of natural philosophy with the growth of Great Britain’s power and prestige,” the aging Banks, assisted by Scottish Robert Brown, seeks to expand both scientific knowledge and England’s prestige in the gathering of specimens from remote climes.

Spurred by the advances in physical knowledge over the recent years, the urgency to know nature’s secrets has spread through the upper classes, an odd mix of serious men and women, their numbers increased by dilettante hangers-on. This quest for knowledge stands in sharp contrast to the drudgery of working-class citizens, a far cry from the scenes on the wharves where incoming vessels disgorge both material and weary sailors after long voyages. Among them, the Solanger is an anomaly, specially fitted to store masses of specimens meant for Sir Banks and Kew Garden (by extension to glorify the unfortunate King George III, currently undergoing one of his “phases”). When six of the returning sailors die soon after their return to England, it falls to John Harriett of the River Police Office and his best man, Thames River Police Chief Charles Horton, to find out who is murdering the sailors and why.

Far from the vast gardens where Banks and Brown seek the intimate knowledge of life through nature, the quest for a killer takes place on the bustling, smelly docks and local environs, the brothels, boardinghouses, taverns and riverways teeming with the demands of commerce in all its forms. Horton’s most immediate problem is to figure out how men can be viciously murdered, their throats slit, blood splattering the walls of their rooms… and yet have beatific smiles on their faces. First one man from the Solander is killed, then two more. When the bloodshed has finally ended, six are dead, all hiding a secret from the island from which they have just returned.

Shepherd possesses a remarkable talent for moving deftly from one end of society to another, exploring the intentions of Sir Banks and Robert Brown in the political milieu in which they operate, then immersing the tale in the machinations of police work on the docks, where captains are kings of their vessels and police investigation is seen as an intrusion, not to mention the territorial squabbles between these authorities. But Harriott’s ace in the hole is Horton, a man with a nose for a new style of investigation heretofore unknown when dealing with criminal activities and very effective in solving crimes of any nature.

With Harriott’s support, Horton pursues the killer, visiting murder scenes, putting together physical evidence, building a case that will lead to the culprit as well as a dark secret that underlies the whole tale. Whatever is amiss began on that Edenic island, where sailors partake of excess and beauty harkening back to Fletcher Christian’s mutinous Bounty and a discovery so precious that men will kill for it. Supported eagerly by his wife, Abigail, an enthusiastic natural philosopher who is with him at the scene of the fist murder, Horton is relentless. Consider the scene of Adam and Eve, the temptation of the seductress (in its patriarchal definition) and the consequences, a drama that resonates in the era of enlightenment, where the temptation for knowledge and the penchant for pleasure are twined into a nightmare of hellish proportions: “Have we done an unthinkable thing?”