Yet they were both thankful. “My colleagues said, ‘You’re the lucky one. You don’t know how many people died,’ ” Ms. Li said.

Of the 28 hours, Mr. Wang said, “It was more terrifying than facing the god of death.”

Like for millions of Chinese, the life they knew was completely eradicated at 2:28 p.m. last Monday, when the 7.9-magnitude earthquake sent wave after wave of tremors through the river valleys and glaciated mountains of Sichuan Province, one of the most beautiful corners of China.

Mr. Wang, 40, had just returned home two days earlier, after traveling around the country for half a year and trying his hand at small businesses. He had lost a lot of money. He and his wife rarely spoke. He spent the Chinese New Year in the city of Guangzhou by himself, skipping China’s most important family holiday.

Mr. Wang is the kind of itinerant worker found in China by the millions, wandering from city to city in these boom years, and so it was chance that brought him home two days before the earthquake.

Ms. Li was raising their daughter, Xinyi, on her own while working at a chemical factory in the town of Luoshui. “My husband doesn’t have a stable life,” Ms. Li said. “He goes wherever he can get a job. I told him, ‘Why don’t you have a rest? Stay away from business. Just try and enjoy life for a while.’ ”

Last Monday, she and her husband had just sat down in her fourth-floor apartment to watch a police soap opera on DVD when the dormitory, which houses dozens of factory workers, began shaking violently.

He flung an arm around her as they sprinted for the bathroom eight feet away. The entire building collapsed right as they got there, knocking them to the ground. The wooden bathroom door slammed against Mr. Wang’s back. Clouds of dust filled their lungs.