It happened in the blink of an eye. One moment, there was little Nathan Fox, a 2-year-old playing in a baby pool with his 6-month-old brother, Joshua, under the watchful eye of their mother, Shawn Fox, an accountant and homemaker from College Park.

The baby was in Fox's lap while Nathan splashed in the sunshine around them. It was a hot summer Saturday, and the family was enjoying a picnic at a community pool with about 40 other students and teachers from a summer Bible school for children and adults located near the University of Maryland.

It was just after noon July 10, and what happened next is still foggy in Fox's mind. She strains to remember the details, but nothing comes.

Somehow Nathan vanished from her view, escaped from the gated baby pool area and strolled along the deep end of the larger pool, which was largely deserted because organizers had just called for a 15-minute break.

That's when the disastrous scenario that is every parent's nightmare became a reality: Nathan tumbled into the water. Barely 36 inches tall and unable to swim, the boy disappeared under the slight waves in an instant, without a sound and hardly a splash.

No one saw this--except 10-year-old David Chung, who was lounging on the side of the pool about 15 feet from Nathan.

David, a novice swimmer who knew Nathan from Bible school, leapt to the rescue, knowing that he could at least stand in the water, whereas Nathan could not.

As Nathan struggled, crying and bobbing in the water, David proceeded to churn his way through the pool, walking from the shallow end to an area about three feet deep, paddling with his hands for speed. He had taken swimming lessons last summer, but he figured he could walk faster than swim.

"I grabbed him around the chest just to lift his head up," David recalled in an interview last week. "He was crying and spitting water out of his mouth."

Once David made it possible for Nathan to breathe again, he screamed for help. Some adults who were nearby rushed to the water's edge and pulled Nathan out of the pool. Lifeguards were on duty that day, but David got to Nathan first.

All this must have happened in a matter of seconds.

"I can't believe I missed him," Fox, 32, said as David recounted the tale that could so easily have turned tragic. "I was trying my best to keep him in the [baby pool] area."

When Nathan was returned to his mother, her first emotion was anger: "What happened? Who told you you could go over there? I was mad at him," she said. "Then it occurred to me that he could have drowned."

Nathan's father, Steven Fox, 31, had dropped the family off at the pool and was busy at home, preparing a lesson for the Bible students.

"It was awfully sobering hearing that story," he remembered. "I spent most of the night thinking about Joshua growing up without an older brother."

Motioning toward David, who was playing with Nathan, Steven Fox said: "I tell ya, that kid is welcome in our house any time."

With two younger siblings, ages 5 and 8, David said he is used to keeping an eye out for small children. He's a shy hero. When asked whether he was proud of what he did at the pool, he said, "A little."

Nathan's father said David was unduly modest. "I don't think the two boys understand the significance of what happened," Steven Fox said. "We'll keep some sort of record of this, and it will certainly be something we tell Nathan so he'll know that David did something really special for him."

As for safety at the pool, the Foxes said they felt that "every precaution was taken" but "it was just one of those things."

Although the incident has done nothing to ease Steven Fox's worries about mixing children and water, it will prompt one definite change: His two boys will take swimming lessons.

"I've always been apprehensive. I told Shawn the water really worried me," said Steven Fox, who is studying for a PhD in electrical engineering at the University of Maryland. "The most important thing is I definitely want Nathan, and later Joshua, to learn how to swim."

The Foxes called The Washington Post with their story because they wanted David to know how much they appreciated what he did and to alert other parents about water dangers.

"If we can help somebody else's child not drown, we're happy to do that," Shawn Fox said.

As for Nathan, he's ready to get back in.

"I like water," he said.

CAPTION: Nathan Fox, 2, left, was rescued by 10-year-old David Chung after he fell into a College Park pool this month. Although David is only a novice swimmer, his quick thinking prompted a rescue before Nathan was seriously injured.