Ariel Lee for The Wall Street Journal

MY MOTHER FLEW home to China in checked baggage.

Mom and I often talked about the trip we'd someday take together to the "city of eternal spring" where she was born. In Kunming, she said, the fruits are sweeter, the mountains look like Chinese paintings and the weather is always perfect. I promised that I would go with her when my life was less hectic, but the years inexorably slipped past and suddenly, it was too late.

As she lay dying, I made the promise one last time. Yes, Mom. We'll go to China.

Nine months after her death, I fulfilled my vow. Worried that the TSA would confiscate her cremated remains from my carry-on, I packed the urn containing my mother's ashes into a suitcase filled with gifts for my Chinese relatives and entrusted the lot to United Airlines.

At baggage claim, my family and I were met by dozens of excited relations I'd never met before. Both my parents were Chinese, but I couldn't understand a word these relatives were saying—growing up in California, I was so determined to be American that I refused to attend Chinese language school, and I didn't pick it up from my parents' conversations. But my half-Caucasian son, Adam, has embraced his Chinese roots. He translated for everyone, flipping between English and Mandarin while I stood there nodding and smiling—and berating myself for having become just another clueless foreigner.

Outside the airport, Kunming looked nothing like the quaint town my mother had described. Instead I found an eight-lane freeway jammed with cars and a skyline studded with blocky high-rises. I'd long suspected that my mother had wildly embellished her stories of China, and I wondered what else had been an exaggeration.

But in the days that followed, we ventured beyond the modern city, into Yunnan Province. The Stone Forest, a set of towering rock formations, truly looked like a work of art. The ancient towns of Dali and Lijiang, the glacier surrounded by green hills on Jade Dragon Snow Mountain, the markets with their sweet, sweet peaches—all were as wondrous as she had promised. This was the China she had wanted me to see, a land that was not merely the fantasy of an aging woman. My mother's China was real.

On the day of the funeral, my relatives drove us out of the city in a caravan of cars, to a neighborhood of dirt roads and crumbling buildings. I was bewildered when someone handed me a black umbrella. Adam explained that we were taking my mother's ashes to visit her parents, but that she had to make the journey in shadow. Adam carried the urn; I held up the umbrella. We climbed a half mile up a dirt track, past stray dogs and chickens, and waded into a cornfield. Unprepared for this hike, I slipped and slid in my sandals; my feet were coated in mud by the time we arrived at my grandparents' tomb.

I imagined my mother's spirit, merrily puffing away in the afterlife.

My Chinese relatives reached into the many bags they had carried up the hill, pulled out gardening gloves and hedge clippers with which to clear away the weeds, and set my mother beside the tomb so she could visit. They burned incense, planted colorful paper flags to ward away evil spirits and laid out fruits, cakes and cookies for the dead to enjoy. I was startled to see them place two cigarettes beside my mother's urn. Her smoking was a habit I long deplored, and I almost blurted out: "Take those away, they're bad for her!" Then I imagined my mother's spirit, merrily puffing away in the afterlife.

After the visit, we carried the urn back down the hill. Another hour's drive took us into cool and forested mountains, to the serene Buddhist mausoleum where the ashes would be entombed. In China, the dead are not forgotten—my relatives cheerfully pointed out all the niches of deceased friends and family, as if gesturing at the homes of the living.

Buddhist monks led the ceremony, and although I claim no religion, I found myself dutifully bowing and chanting words that I did not understand. It was my brother's duty to clean our mother's eternal home, so he wiped down the niche and placed the urn inside.

It was my duty, as firstborn, to close the door and lock it.

I hesitated. My hand caressed my mother's urn. I thought of the turbulent journey that had been her life. How she had escaped war-torn China, leaving behind everyone she knew and loved, and never again saw her parents. How she had struggled as an immigrant in America, endured an unhappy marriage to my father and nursed a lifetime of regrets. She was back where she was born. Home at last.

I was sobbing as I locked the door.

There was one final ritual to perform. Before you leave a cemetery, someone must call out your name and say: "We are going home." You must answer: "Yes, I am going home now," so the spirits know you are departing. The relatives queued up, waiting for their names to be called, and one by one they left.

Tess Gerritsen

At last it was my turn. My son called my name and said, "We're going home."

But it was to my mother that I spoke when I answered: "I am going home now." To my own home, in America.

—Ms. Gerritsen is a retired physician and the author of more than a dozen thrillers, including the recently published "Last to Die," part of the Rizzoli & Isles series.