The route from journalism to authorship of fiction is well marked, which is no surprise given the fine line that divides the two.

Mark Douglas-Home is a former editor of The Herald which, when was it called the Glasgow Herald, incubated the careers of a number of novelists, including William Watson – aka JK Mayo – who should be better known than he is and, most notably, George MacDonald Fraser who, as he was putting tomorrow's fish-and-chip wrapper to bed, was dreaming of that incorrigible cad Flashman.

Douglas-Home's chosen genre is crime, which even as it declines on the streets proliferates in the bookshops. The first thing to say about The Woman Who Walked Into The Sea, his second novel to feature Cal McGill, an oceanographer who specialises in solving mysteries through his knowledge of tides and currents, is that it is infinitely better written than the majority of its competitors. Moreover Douglas-Home is not the kind of writer who hopes to seize a reader's attention by pandering to humanity's fascination with torture or by offering a DIY guide to dismemberment, for which much thanks.

The novel is set in the north-west of Scotland, in and around Ullapool, in an imaginary village called Poltown, a carbuncle that was built in the 1960s to accommodate workers at a Nato refuelling deport, POL being short for Petroleum, Oil and Lubricants. The latest threat to the area's scenic beauty is an offshore wind farm, but while that offers an interesting contemporary backdrop to an intricate plot, it is really a red herring. Rather it is the woman referred to in Douglas-Home's title who is at the heart of this always entertaining and gripping mystery.

Her name is Megan Bates and it's believed she drowned herself and her unborn baby after she was rejected by William Ritchie, owner of Brae House and "a big-shot lawyer" who commuted between Edinburgh and the Highlands. But did Megan really kill herself? That is the question which demands to be answered and why her daughter, Violet Wells, a single mother with a young child, travels north from Glasgow 26 years later.

It is a promising scenario and Douglas-Home resists the temptation to inject it with more drama than is necessary. The novel's pace is perhaps slower than some other crime novels but, like PD James, say, it allows more time for reflection. In classic crime fashion, Douglas-Home offers a multiplicity of suspects who may have been implicated in Megan's death. Among them is Duncan Boyd, a simple-minded beachcomber who, like the farmer on the Menie estate stubbornly defying Donald Trump, refuses to sell his land to those who want to acquire it for the wind-farm development.

Other potential suspects include the Turnbulls who, at least in a former incarnation, behaved like rural kin of Tony Soprano, and, of course, there are the current inhabitants of the Braes, Matt and Alexandra Hamilton. By patronising and insulting their former housekeeper, Mrs Anderson, they bring back to the surface family secrets which they hoped had long been buried.

In less assured hands such an extended cast would soon run out of control. But Douglas-Home's straightforward and unpretentious method of storytelling – in which the similes can be counted on one hand – ensures that this never happens. Inheritance, that mainstay of 19th-century fiction, and which, alas, has by and large become redundant as a motive for murder in the modern era, is critical in this novel, as also are class and the notion of Them and Us. As Mrs Anderson remarks: "Inheritance is a way of life around here. The land-owners pass on their acres, the Turnbulls their scams."

In such a divided, conservative and insular community it's the outsiders who import change and stir things up. Cal McGill's excuse for visiting is an invitation from Duncan Boyd, who has found a King Neptune Scroll, one of ten of thousands of messages placed in bottles and dumped at sea by Guinness in 1959 as part of a marketing campaign.

Recently divorced and with both of his parents dead, Cal is perfectly placed from a fictional point of view for a long and intriguing future. Here, however, his presence is less imposing than it might be.

He does not, for example, dominate the action as those charged with detection typically do. This may be deliberate but I'd rather see more of him than less. In the meantime, television producers with prime-time slots to fill may consider the sea detective the answer to their prayers.

The Woman Who Walked Into The Sea

Mark Douglas-Home

Sandstone Press, £8.99