The Woman in the Water” is an interesting, somewhat offbeat novel about a young man determined to do what he wants with his life. The setting is Victorian England, and Charles Lenox — the son of an earl — declares he wants to be a private detective, London’s first. In 1850, the idea that a private citizen, especially one of Lenox’s social position, would proclaim this as his career choice is odd, especially among Lenox’s family and friends. But Lenox is adamant. Lenox is an endearing character, here making his 11th appearance in Charles Finch’s outstanding series.

The novel, a prequel, begins with Lenox, 23, and Graham, his valet, friend and fellow sleuth, in Lenox’s elegant apartment in St. James’s Square searching the morning papers for crimes to solve. They are excited by a letter in a tabloid in which an anonymous writer claims to have committed a perfect crime, a murder, and — because the newspapers have taken no notice — warns that another will soon follow.

Lenox thinks the first murder may have been that of a woman whose body was found on a small island in the Thames and whose identity remains unknown. He takes his suspicions to Scotland Yard, where detectives scoff at him. Then a second woman’s body is found beside the Thames, and the murders explode into front-page news. One newspaper headline calls the second victim the “Thames Ophelia,” which garbles Shakespeare but sells papers.

The director of Scotland Yard finally agrees to let Lenox and Graham join its investigation. In time the murders will be solved, but they are not the most interesting element of the novel. Finch is good at examining the subtleties of his characters’ relationships. Here his somewhat confusing crime story impressed me less than Lenox’s dealings with his family, as well as his frustrated passion for the lovely Elizabeth — Lady Elizabeth — who is 19, charming, beautiful and inconveniently married to another man. (“He had never proposed. He felt a familiar dull pain at his lack of courage; he had missed his chance.”)

Elizabeth’s husband is away with the army, she and Lenox often meet socially, and he cannot hide his love for her. In one of the novel’s most dramatic moments, Elizabeth tells Lenox candidly what an impossible position he has put her in. “Think for a moment in your simple life what it means to be a woman, Charles,” she begins, and her anguished words are as painful for the reader as they are for Lenox.

Lenox’s mother, father and brother are admirable people who lead exceptionally pleasant lives — except that, early in the novel, his 61-year-old father is diagnosed with cancer and given six months to live. This leads to poignant scenes between father and son, including a spur-of-the-moment train trip to St. Petersburg.

Finch is an elegant stylist who captures vividly places and characters:

“It could be argued that the Thames hadn’t changed in 7,000 years. Or — that it changed at every second, and in every decade, and in every century, while remaining eternally itself.”

“Elizabeth was wearing a light brown dress, light brown curls falling around her face. There was that Gioconda smile in her eyes: It was how Lenox had always pictured Jane Austen, actually, deep brown eyes that missed nothing, took it in, saw the humor and irony in it, and refused to pass judgment.”

Finch offers fascinating glimpses of London life. There’s the hippopotamus who recently arrived from Egypt — “traveled up the Nile with an entire herd of cattle to provide it milk.” Thousands of people a day are crowding into the London Zoo to see this creature.

We also meet an old, rich, eccentric engineer who tells how, when he was young and penniless, he spent his last 14 shillings to buy dozens of pieces of brass — coils, springs, screws — and spent nine days creating a small brass frog. (“When you turned its lever it jumped over its own head.”) He sent the frog to a prominent man’s granddaughter for Christmas, which led to his first job and eventual success.

Hippos, brass frogs, Russian trips, unattainable love, the doomed Thames Ophelia — fans of the Lenox novels will enjoy these glimpses of Charles’s early life. And those new to his work will find here a persuasive portrait of Victorian England.

Patrick Anderson writes regularly about thrillers and mysteries for The Washington Post.

Read more:

The Woman in the Water

A Prequel to the Charles Lenox Series

By Charles Finch

Minotaur. 292 pp. $25.99