There's a fine line between sainthood and nitwitcy, and my husband and I glimpsed it recently while caught in the undertow of an impulsive good deed.

There's a fine line between sainthood and nitwitcy, and my husband and I glimpsed it recently while caught in the undertow of an impulsive good deed.

Not that I consider us candidates for sainthood. Perhaps I meant to say there's a fine line between fundamental decency and nitwitcy, and those who cross it may regret reaching out in the first place.

I don't regret it, exactly. The most alarming result of our small adventure was the look on my younger daughter's face when I told her the story. The look was the one parents get when their teenager starts explaining why he's calling from the police station.

Here's what happened: My husband and I were driving home one evening -- indeed, we were approaching our own mailbox -- when we spotted a figure walking a bicycle along the road. We wondered who could be out there in the dark on a busy highway, and after we'd unlocked the house, my husband said he was going back.

No doubt he was thinking, as I was, of the evening years ago when we came across a young woman striding briskly along our road's sidewalk-less berm. She was walking to a village she thought was around the next bend, but in fact, it was miles away, up- and downhill, past farms and fields and on the other side of the interstate, for heaven's sake.

"You can't walk that far," we told her. She insisted, we insisted, and soon we had the awkward experience of waiting with a stranger in our living room for someone to pick her up. We only hoped that as the friend drove her to the village -- drove and drove and drove her -- she realized how right we'd been.

But about the bicycle walker. After warning me that he might bring the person back ("Fine," I said), my husband did bring him back. It turned out he was a she named Gloria, a woman neither young nor small nor fragile. She was far from hulking, but trust me, she could hold her own.

Like good hosts, we waved at our downstairs bathroom. Did she need ... ? She obligingly stepped into the room, looked at pictures of our daughters as small children and stepped out again.

"Are those your grandchildren?" she asked.

"No, our daughters. They both just had babies," we said, partly to make conversation and partly because if we were ordered before a congressional subcommittee, we'd find a way to let the record show our two grandchildren.

We sat down to grilled cheese sandwiches. "How did you come to be on the road?" we asked Gloria, and she told us she was bicycling across the country.

We pounced on her answer like puppies on a chew toy. Traveling across America! we said happily. Like the world walker! Lucky you!

"Do you have any children?" asked Gloria, and we shut up.

Two, we answered. We didn't bother to mention grandchildren.

I asked where her cross-country adventure began, and Gloria said she'd left Texas for a job in California.

"But it didn't work out," she said. Her story -- in which she was a constant victim of unfairness -- culminated with her decision to take off on a bike. Only not this bike, she said, meaning the two-wheeler still in the back of my husband's truck. Several bicycles had been stolen practically out from under her, she said. One disappeared while she slept on a rest area picnic table.

By this time, my husband and I had realized that far from being a pedaling Rick Steves or another Cheryl Strayed, finding her true self on a bike instead of the Pacific Crest Trail, Gloria was a homeless person.

Well, and so? we thought. We were glad to share our cheese sandwiches with someone in need, whether the person was an adventurer or just hungry. Still.

"Do you guys have any children?" Gloria asked.

My husband put down his napkin.

"How can we help you?" he said. His question answered the one that had been hovering over the supper table like a low-hanging cloud: She would not be spending the night in our house.

"Well, I'd hoped to find a campground," Gloria said. If she'd hoped to find it in our living room, she didn't say so. We were glad to tell her of several such places. She chose one, eventually -- "I'll take you," my husband said -- and soon they were gone.

A very long time later, my husband returned. No one had been in the park office, he said, so he'd suggested Gloria pick a spot and see the park people in the morning. (She was no more likely to do that than she was to pull an Airstream trailer out of her pack, but never mind.)

She'd been reluctant to pick a spot, and my husband had circled the grounds several times, while the few campers watched them warily. She finally chose a site near the showers, then wouldn't open the passenger door. A park security cruiser passed them twice, and my husband had resigned himself to answering questions when Gloria finally climbed out. My husband lifted her bike and her backpack from the truck bed and wished her luck.

For days, we looked for Gloria whenever we were out, but we didn't see her again. She'd pedaled on.

ThisWeek columnist and copyeditor Margo Bartlett.