Rupert Thomson’s strange yet stimulating last novel, “Katherine Carlyle,” followed a gutsy, strong-minded woman who trusts fate, relies on strangers and ventures into unknown territory on a mission to find inner calm and deeper meaning. “Sometimes I have to prove that I exist,” she tells her reader at one point, “that I’m vibrant on the inside.”

The focus of Thomson’s latest novel is not one but two singular women who are so vibrant on the inside that they practically glow. While “Katherine Carlyle” chronicled an episode in a life, “Never Anyone But You” goes further by mapping whole lives — and real lives at that. With skill and verve, Thomson relates the largely untold story of two unsung heroines who set out to defy convention and ended up resisting the Nazis.

In 1909 in the French city of Nantes, 17-year-old Suzanne Malherbe meets Lucie Schwob. Both are creative: Suzanne has a passion for drawing; Lucie has an ambition to write. What starts out as a close friendship soon turns into a passionate relationship.

“You have to make yourself,” Lucie tells her illicit lover, before announcing that she is changing her name to Claude Cahun. Suzanne reinvents herself as Marcel Moore (“I liked the way it loitered between the genders”). After the cataclysm of World War I and Claude’s breakdowns, suicide attempts and stint in a Swiss sanatorium, the pair leave their provincial, patriarchal milieu for the Bohemianism and liberating atmosphere of Paris. “We’re original, unique,” Claude says. “We need to live in a place that recognizes that.”

In the capital, they make their mark and mix with some of the great cultural figures of the day, including Dalí, Hemingway and André Breton. However, with mounting anti-Semitism and the distant rumble of another war, the women swap the dazzle of the City of Light for peace and isolation on the island of Jersey.

“It’s independent and awkward and oddly fierce,” Claude muses. “Like us.” But when their retreat is invaded and occupied by Hitler’s forces, they risk all they have by waging a propaganda campaign designed to “give the Germans something to think about.”

As its title suggests, this novel is primarily a love story, and Thomson delineates the tender moments and the dark patches in a romance that lasts a lifetime. But his characters are not only lovers. One of the reasons they come so thrillingly alive on the page is because he successfully portrays them in many different guises — as artists, socialites, iconoclasts and resistance fighters. In each case he gets under their skin and into their minds.

The book’s interwar Paris section expertly conveys the glamour and intellectual activity of that era. The Jersey section depicts a gripping cat-and-mouse game of courageous acts — and terrifying consequences. In all sections of this remarkable novel we find ourselves cheering on two fearlessly individual women who opted to live “instinctively, and without restraints.”

 Malcolm Forbes has written for the Times Literary Supplement, the Economist and the Daily Beast. He lives in Edinburgh, Scotland.

Never Anyone But You
By: Rupert Thomson.
Other Press, 350 pages, $25.95.