The curveball thrown by my 9-year-old nephew came barely an hour after we'd landed in London.

The flight from Los Angeles had taken 10 hours; the walk from the arrival gate to Heathrow's immigration counter felt almost as long. There was a lengthy tramp to the Underground, which rocked and rolled 50 minutes into the city. By the time a bedraggled Julian stepped off the Piccadilly Line, he had sore feet, was fatigued and maybe a tad woozy.

A packed escalator climbed out of the Underground station through a corridor of advertisements for West End shows. Somewhere between the posters for "Mamma Mia!" and "Les Misérables," Julian covered his mouth. His eyelids fluttered and then came the nausea, which gushed onto his shirt, jacket and pants.

All eyes above and below were upon us, but our sober-faced fellow passengers were speechless. In unison, their heads pivoted away.

Uncle David was on his own.

I'd long looked forward to the day when my youngest nephew would be old enough to appreciate his first adventure abroad. London was an easy choice: It's one of my favorite cities and, thanks to the History Channel, Julian had a vague awareness of it. Better yet, airfares were as low as I'd seen in years, and last March the British pound surrendered to the Yankee dollar, reaching a 23-year low.

Julian's parents were elated to entrust him to my care -- a passport was ordered.

No sooner were tickets purchased than a flood of doubts emerged. Was seven days sufficient to conquer jet lag? What if we became separated?

Most urgent: How to entertain a child for a week straight?

I plotted carefully. A flight arriving in the afternoon would help surmount jet lag, I reasoned. I had Julian's teacher give him an assignment -- a daily report on the trip. I sought advice on kid-friendly attractions that might prove more engaging than my own fave, the British Museum. And my sister prepared a detailed list of instructions.

But nothing prepared me for the deluge that occurred halfway up our first escalator. Mortified at the prospect of checking in to a hotel with a 9-year-old covered in regurgitated airplane yogurt, I sought out the Underground station attendant for help. Discerning slight panic, he took pity and showed us to the station's private bathroom, where Julian changed and rinsed his face.

"I'm feeling better now," Julian chirped while I surveyed the wreckage of his soiled clothes. He pulled on his remaining clean coat, a lime green ski jacket that became his de facto uniform for a week.

We emerged from the station into a crisp blue spring day that was ideal for a ride on the London Eye, the world's largest "observation wheel," which offered CinemaScope views up and down the River Thames. On a double-decker bus tour of the city, we sat on the open top deck as Fleet Street's mishmash of architectural styles passed overhead.

Those first-day activities were planned to keep Julian awake, but he succumbed to the jet lag during a rush-hour traffic jam aboard the double-decker. During the rest of the trip, he happily stayed up till 10 each night and never had a problem rising by 8 a.m. for breakfast (a dose of the natural hormone sleep aid Melatonin the first three nights helped).

Another tactic paid off in ways I didn't expect. I told Julian I'd count on him to serve as our navigator. He took to the task like a rat to a maze. When I told him our first destination was the London Eye, he scoured the map.

"OK," he announced, tracing his fingers along subway routes. "We'll take the Piccadilly Line to Leicester Square, then transfer to the Northern Line and get off at Waterloo."

By the end of the week, it almost seemed the reason for our trip was to ride the Underground, interrupted by stops at assorted points of interest. Once he was able to memorize the name of our hotel and identify a policeman, I began to think that getting separated wouldn't be the end of the world.

The chance of that happening was slim, thanks to a friend who suggested that Julian wear bright colors. At the changing of the guard at Buckingham Palace, crowds descended and blocked Julian's view, but I let him roam the fountain area facing the palace to find the best perch. Julian's lime green coat was illuminated in a sea of drab.

• • •

As an only child, Julian is used to interacting with adults and is a good eater, open to trying new things. Well, most things.

Grilled English kipper?

"No, thanks."

How about some black pudding?

"No way!"

Lambs kidney on toasted doorstop?

"Eeeeww!"

The traditional English breakfast became the favored meal, and Uncle Dave soon discovered what most parents know: Fancy restaurants aren't a high priority for a 9-year-old. Instead I learned that a reliable sign of quality is whether pizza's on the menu.

We did splash out on one occasion for a proper English afternoon tea at the Ritz Hotel's Palm Court.

As a pianist eased through standards and we were shown into the so-tasteful room, I quickly concealed Julian's lime green number behind a potted palm next to our table.

The kid must have had a formidable sermon on etiquette from his grandmother; no sooner did we sit down than an unexpected reserve of manners blossomed. The napkin went into his lap, his back went upright and with budding aplomb, Julian surveyed a roomful of high society surrounded by pink marble and gold-leaf trim.

One question was on Julian's mind, and I assured him our waiter would be a good person to ask.

"Does the queen ever come here?"

"Oh yes," the waiter replied. "She comes here for birthday celebrations and formal occasions. You know, the queen's palace is just across the park."

If Julian felt out of his element at the Ritz, he never let on.

• • •

I never had any doubt there was learning to be gained by taking him out of school for this trip.

I had hoped it would come from seeing historical buildings and by swimming in the customs of a foreign nation. But while buildings and tours have their place, I began to realize that learning happens on its own schedule, often without any order or logic.

The chorus of foreign tongues, the sight of homeless people stretched out on makeshift sofas in the Underground and buskers seeking donations for quirky sideshows all broadened Julian's world beyond anything he'd experienced in his San Diego bubble.

David Swanson is a freelance writer based in California.