At 73, Isabel Allende is finally old enough to write about retirement with some personal authority, but there’s nothing retiring about her treatment of the twilight years. Although her new novel takes place in what we used to call an old folks’ home, “The Japanese Lover” is animated by the same lush spirit that has sold 65 million copies of her books around the world. While brushing aside the dismal expectations and hoary jokes about elderly people, she captures the real complexity and abiding passion of a long life.

“The Japanese Lover” may be furnished with oxygen tanks and painkillers, but it blasts along like a turbocharged wheelchair. The action takes place at Lark House, which is more a place of unrest than of final rest. Its 250 residents — mostly octogenarians — are “freethinkers, spiritual searchers, social and ecological activists, nihilists, and some of the few hippies still alive in the San Francisco Bay Area.” Before progressing through the facility’s four levels of infirmity — ending in “Paradise” — these senior citizens enjoy a variety of classes, “from painting to astrology”; a cinema club devoted to particularly violent films; and surprisingly effective street protests. (The police don’t fire tear gas for fear of killing them.) “The old folks in the home,” Allende writes, “were conclusive proof that age, despite all its limitations, does not stop one from having fun and taking part in the hubbub of life.”

Like a playwright who knows her characters must never sit down long for dinner, Allende immediately begins expanding this story by focusing on a new, young aide at Lark House named Irina Bazili. A 23-year-old immigrant from Eastern Europe, Irina is inexperienced but delighted to have the job — and some of the randier residents are particularly delighted to have her here, too. Although something dreadful haunts her, Irina’s infectious enjoyment of these old people leavens their lives and buoys the whole novel.

Irina’s favorite resident is an elegant, reserved woman named Alma Belasco, who has recently come to Lark House under somewhat mysterious circumstances. Although still in good health and entirely in control of her affairs, Alma has abandoned her mansion and the control of her family’s philanthropic organization, which builds gardens in poor neighborhoods. Free of those duties, she takes a modest room at Lark House, where she maintains her regal distance. She has no sympathy with the group’s New Age spirituality, and she comes and goes as she pleases, driving around “in a tiny car, completely ignoring all traffic regulations, which she chose to regard as optional.”

Isabel Allende in Madrid on Oct. 13. (AFP/Getty Images)

But where does she go? Who is sending her those letters and bouquets?

“The Japanese Lover” feels, at first, as nutritious as Grandma’s freshly baked sugar cookies. But there’s nothing cloying about this unabashedly sweet story — and nothing unambitious about it, either. Much of the novel is devoted to reconstructing the details of Alma Belasco’s eventful past life, and in that pursuit Allende sweeps across the second half of the 20th century, gathering in these chapters the Nazis’ atrocities in Poland, the French Resistance, the internment of Japanese Americans and the AIDS crisis — all captured in quick but affecting scenes. Clearly, there’s enough raw material here for a book three times as long, but Allende’s graceful telling, although often breezy, never frays or grows superficial. (The novel’s heavy advocacy for legal euthanasia is a rare clunky element.)

This is an author who knows how to set and keep a fast pace, who understands that beneath all our poses of literary sophistication, most of us still want a rich, engaging story. When President Obama presented Allende with the Medal of Freedom last year, he put it well: “Her novels and memoirs tell of families, magic, romance, oppression, violence, redemption — all the big stuff. But in her hands the big became graspable and familiar and human.”

Much of the success of “The Japanese Lover” stems from its ability to keep the past and present stories equally engaging — to reflect, in a sense, these alert residents, who can reminisce without losing interest in their current surroundings. Alma’s history, as the title suggests, includes her relationship with a Japanese American at a time when such a romance was unacceptable to her family and peers. But having outlived those racist decades, Alma may have a chance for the happiness that was denied her long ago. And that romantic suspense winds around the much darker story of Irina’s past, which is stained by a crime so ghastly that she’s determined never to let anyone close again.

Allende, who was born in Peru and grew up in Chile, continues to write her fiction in Spanish, although she speaks English fluently. This smooth translation, by Nick Caistor and Amanda Hopkinson, conveys the author’s charming humor with just the right light touch. Allende’s control — or her translators’ — falters only during a couple of florid love scenes when we’re subjected to such contortions as: “They locked themselves in a cubicle and spent until dawn immersed in pleasure, going at one another like wrestlers and wallowing in the entwined delirium of their bodies.”

The most appealing aspect of “The Japanese Lover” is that, despite its fearless engagement with horrors on both a national and personal scale, it remains a story of genuine and refreshing generosity. Allende manages to blend domestic comedy, historical fiction, mystery, romance and even a note of fantasy to create a novel that’s a pleasure to recommend.

Ron Charles is the editor of Book World. You can follow him on Twitter @RonCharles.

On Nov. 13, at 7 p.m., Isabel Allende will be in conversation with former Book World editor Marie Arana at Politics & Prose Bookstore, 5015 Connecticut Ave. NW.

The Japanese Lover

By Isabel Allende

Translated from the Spanish by Nick Caistor and Amanda Hopkinson

Atria. 322 pp. $28