Unclear, too, is whether her husband, the malodorous Bob Watson, is involved in the espionage. Nor do we know for whom his partner – the glamorous and mysterious Percy Fuller, who is Mary’s contact – is really working. But they all end up on the island, along with two Chinese servants, some Kanakas, some pesky Aborigines who remain a threat and may be killing off the chooks (then again, it might be the large eponymous lizards), and a genial character named Porter Green, who works on the boats. Mary has also managed to import her reluctant younger sister to the island to save her from their father’s incestuous depredations. Things go from bad to worse, as they do in romantic fiction. Captain Roberts, dark and bearded, acts as puppet-master, and looms in the background with titanic omnipotence. Mary has to muster all her grit to deal with the calamities. Rather plain, she has to rely on quick wits and a punchy verbal style.

The media release for this book suggests that it is situated at the literary end of historical fiction and that it carries historic authenticity, while the back cover tries to substantiate its claim to literary writing by noting that Judy Johnson won a Victorian Premier’s Literary Award in 2007 for her verse novel, Jack.

But the proof of literary merit is in the writing, and this novel is an uneasy mix of overwrought romantic fiction stylisations (a thrilling tale of peril and intrigue) and a heady tendency to prolix metaphor. It is sand-trapped with similes. Just when you think you are metaphorically out of the woods, you find yourself in the rough with yet another interruption: ‘Only now is the breeze creeping in: shivering off the overbite of the reef … the tied-up dogs growl, the sound like sacks of rocks rolled back and forth in their throats … A yolk-yellow moon hangs low in the cloud-sling of the sky …’ Or this, when sipping whisky: ‘The ice makes small cracking sounds as it surrenders to the potent liquid ... It’s strong, like swallowing bull ants in liquid form.’ Or this, watching horses drink: ‘A dozen hinged and bristly coconut halves open and close, scooping water.’ Horses do not scoop, they suck. ‘And over the lot, the great, dripping damper of the sun.’ This metaphorical style is so distinctive and high-flown that it overrides the ordinary tone of the narrative, and would be more believable emanating from a graduate of a tertiary institution than from a publican’s daughter living in the rough pioneer world of far north Queensland in the 1870s.

In a preface, the author quotes from the found diaries of the real Mary Watson and from Robert Watson’s deposition to police. Both entries are terse and plain, in stark contrast to the fictitious Mary’s speaking style and to the diary entries at the start of each chapter. These read like over-educated aphorisms, with a hint of Jane Austen: ‘Keen observation is a skill that the homely find useful,’ Mary avers on 12 May 1879.

Johnson might be trying to realise a new cross-genre, speculative historical fiction. While I do not deny authors the right to speculate about historical figures’ emotions, it seems odd to equivocate about the facts of a case on the public record. You can’t have it both ways – quote actual diary entries and then blithely invent a whole new set of circumstances at odds with the known facts – or can you? There are no rules for creativity, though an interpretative slant that embroiders the true story seems unnecessary.

Perhaps the perfect literary novel is judged to be one that wins lucrative literary prizes and has big sales figures, but another set of criteria suggests that it must disturb our sense of ourselves in society, meet high critical standards, and preserve literary values. It needs to tell us something about the human condition that we might have missed. Popular novels, by contrast, let us off the hook and don’t worry too much about the complexities of motivation, the intricacies of psychology, or the known facts.

I don’t need smuggling and intrigue to keep my interest, or a heroine in a frontier myth made ersatz for public dégustation. I would rather ponder the ambiguities of our social history and the implications of Mary Watson’s true and fateful tale, whose stark reminder of a sordid past remains extant.