Seven thousand miles was a long way to go for a tiny scrap of paper. The note was pinned to my daughter’s sweater when she was found at seven weeks old on a bridge in Yixing, China. That’s what I had been told by the adoption coordinator there who had placed her in my arms.

This search was set in motion 15 years ago when, at 3, Sophie was astonished to learn from me that all babies don’t come from China but from inside their mothers. When I explained that another woman had given birth to her, not me, she protested.

I could not bring myself to utter the well-meaning evasion that she was “born in my heart,” as had many adoptive mothers I knew. But it didn’t matter what I said; her world had been upended and she kept trying to right it.

At 4, she said, “Mommy, I always think: How was I made? What was I made from? Was I made from someone?”

This was bewilderment; this was grief.

At 5, after I had tucked her in one night, she said, “But why did she give me away? Did she not like me?”

“Sophie, I’m sure that she loved you.”

“But why did she not like me? Why did she throw me away?”

At times she would plead, “Mommy, do you know her? Can we call her?”

Her questions made my heart hurt, as did the awareness that the very system that had allowed me to adopt her also made me complicit in severing her roots.

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Sometimes when I held her, I would think “bone of my bones, flesh of my flesh,” before realizing the phrase was not mine to say, that there were two people walking this earth who could say it. I wanted Sophie to have a chance to find them. The only possible link between her and the part of herself she had lost on that bridge was the note.

Our age gap added urgency to the search. I would obsessively do the math: When she’s 20, I’ll be 70. When she’s 30, I’ll be 80. At some point, too early in her life, I’ll be gone. I believed that, as she matured, it wouldn’t be enough for her to know that she was part of a generation of 35 million lost daughters who, under the “one child” policy, were apparently aborted, abandoned or worse. Or that she was born into a culture where bloodlines pass through sons and folk wisdom holds that you’re better off raising geese than girls.

I knew my child. She would long for a reason more specific and personal. I wanted her to have whatever evidence could be found before it went missing or before I was no longer here to help her find it.

I began to dream of that note. I questioned those who had helped me adopt her, both in the United States and in China. I visited Chinese officials. All were kind and responsive, but the note never surfaced.

Then, when Sophie was 11, we had the opportunity to return to China on a winter tour. By this time, she no longer asked about her birth mother; she was preoccupied with “The Hunger Games,” her friends and convincing me to get a dog. She no longer enacted abandonment scenes with her toys; she spent her downtime practicing the horse dance from “Gangnam Style.” Her past no longer seemed to haunt her, but it did me.

After the tour, I arranged a trip to Yixing, the small city in the Yangtze River delta where she was found. If that note still existed, it would be there.

On a gray day in early January, we set out with our driver and translator. I was glued to the frozen landscape out the window; Sophie was glued to her iPod.

Our first stop was Yuedi Bridge, where, on August 4, 2001, at dawn, a passer-by heard the cries of an abandoned child. I had imagined one of those elegant crescent bridges in ancient Chinese paintings, but Yuedi Bridge was a concrete slab over a polluted canal.

As we walked across, I wanted to prostrate myself to the goddess of second chances who had granted me this child when I had all but given up on motherhood.

Fighting tears, I glanced at Sophie and saw that her face was also clouded over.

“Honey,” I said. “I know. This is hard.”

“Mommy,” she said, choking up. “This is so boring.”

I said nothing but pulled her close.

Whoever found Sophie had taken her to the local police station, the one place I hadn’t contacted as I couldn’t determine the precise precinct from the records. That was our next stop, and soon we were standing before a woman we hoped could help. But she said to our translator with a smile: “Records before 2005 were lost in a fire.”

“How can you smile?” I said. “A part of my daughter was lost in that fire!”

Sophie looked panicked. “Mom, stop it. They’re going to put us in jail!”

“O.K., we should go now,” the translator said.

Our last stop was the orphanage where Sophie had spent nine months after being found, a place that seemed stuck in time. When I adopted Sophie, Yixing was covered in ancient soot. There was nowhere for a foreigner to sleep. Now, there were 30 hotels. The China that had produced a generation of abandoned girls was quickly being swept into the past.

We were introduced to the new director who said that Sophie looked like “a local girl.” She instructed my daughter to study hard, help others, always love her mother and take care of me when I am old.

Sophie managed a polite smile, though I sensed her eye roll.

As we were leaving, the director handed me a file. I began to leaf through and saw the adoption papers I had signed 10 years before. Then I noticed something stuck between two pages: a torn, weathered bit of notebook paper with ballpoint scribbles.

I lifted the weightless scrap. The lines had faded. There were a few Mandarin characters and numbers. I deciphered Sophie’s date of birth, which of course I knew, and the exact time of her birth, which only her birthparents could know.

This was the note.

I handed it to Sophie, who glanced at it, then gave it back.

She seemed unmoved, but I was overcome. Through tears, I snapped image after image.

Back in the car, Sophie said, “The note said nothing, so why did we even go?”

I, too, was disappointed at how little was there, but I remembered reading of birth mothers, about to leave their girls, who had written pages, only to tear them up in shame and scribble a birth date instead. One birth mother had even sewn her baby an outfit of patterned cloth from which she cut a patch — a precious bit of proof to be preserved, perhaps, until the day they were reunited.

I knew one thing for sure: Even in its brevity, the note was evidence that my daughter was left to be found. She was not left to die.

Sophie is now 18. This child who once clung to my chest like a barnacle now lounges across the couch, a rope of hair swung over her shoulder, ice packs tied to each knee after track practice.

“Mommy, massage my feet?”

These days, it’s the only physical contact she invites. I’ll take what I can get. I knead her soft soles, notice her toenails, pearly and perfect. I ask what she thinks about our quest for the note, hoping she’ll acknowledge that words from her birth parents, few as they were, mattered.

“I didn’t care about the note,” she says. “You did. You made it about you and it’s my story, not yours.”

Had I missed how let down she might have felt by this scrap that we had pursued so fiercely yet said so little? Had I missed how pushy I may have been with my guilt, my determination and perhaps even my projection of abandonment and loss?

Had I not turned the note into my great white whale, perhaps I would have noticed that, at 11, Sophie was busy growing up as a beloved daughter in America. And while I had believed the note might help reconnect her severed roots, her annoyance made me wonder whether any human being can tell another what they need to feel tethered.

As for whose story it is — it’s Sophie’s, of course, but it’s mine too. Beyond my own desire to know what the note might reveal, I saw it as my only link to the people whose loss had led to my gaining the privilege of nurturing a child and watching her life unfold. Who were they? What had they suffered in abandoning their daughter?

After all, it’s their story, too, but one that is hidden from us, existing only as a scrawled fragment, a few marks on an otherwise blank shred of paper.

Robin Reif is a writer in New York City.

Modern Love can be reached at modernlove@nytimes.com.

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