By Lap 18 of the 20-lap race, Luk is swimming all alone. Drama builds with each stroke because those watching Luk can't believe what they are seeing. The clapping is increasing, the cheering is becoming more boisterous and the chanting is growing louder, "Go, Andrew, go."
"It's amazing and wonderful," said Eve Chen, the mother of a Diamond Bar swimmer.
Luk's story is more than inspirational. It's a triumph of the human spirit.
Luk joined Diamond Bar's junior varsity swim team last month after much agonizing over what he should do with his life.
At 5, he lost his vision because a 1.1-centimeter tumor damaged his optic nerves. Radiation reduced the tumor's size, but its location on the brain stem made it too risky for surgery, leaving him blind and partially deaf. He can detect light and darkness from his left eye but nothing from his right eye.
As the years went by, he'd swim for fun, but making the decision to join a team was never considered, until last year.
"It was a need to be part of something and get out and do something I enjoyed because for a long time I've been sitting around and talking about what my future could hold but never got up and did anything," he said.
With the urging of teachers and counselors, he enrolled last summer in a competitive swimming program at Mt. San Antonio College run by Jodi Lepp, an age-group instructor for Brea Aquatics.
"I thought it was awesome that he had no fears of jumping in and was willing to get his feet wet," she said.
She taught him fundamentals of swimming competitively, though she had never worked with a blind student before. Through repetition and learning to count his strokes, he figured out when he would be approaching a wall.
"If you practice it every day, you get more comfortable," Lepp said. "The thing I love about Andrew is that there are other kids who will complain, 'My toe hurts, my leg hurts.' And he goes, 'What's next?' He motivates me."
Luk joined Diamond Bar's swim team in February. He was a 16-year-old sophomore welcomed with open arms by Michael Spence, a dedicated, always positive veteran coach who has a Santa Claus-like white beard and a "big heart," as one parent put it.
Spence immediately endorsed the idea of Luk competing for Diamond Bar. And he assigned one of his varsity swimmers, senior Lynn Han, to serve as his mentor and personal coach.
Before each race, Han takes Luk by his arm and guides him to the pool rail, where he gingerly drops into the water for competition. Han is one of two tappers who hold a 75-inch long white pole with a tennis ball fastened at the end to touch Luk as he nears each wall. It's the way he avoids banging his head when he loses count of his strokes.
Han has taught him how to refine his stroke and swim in a straight line within his lane.
"He's competitive, he's passionate," she said. "His attitude is determination."
In his first race this month, Luk's time in the 500 free was 9 minutes 55.14 seconds. Two days later, his time was 9:32.45. In his next race, it dropped to 8:54.28. The personal bests keep coming, and last week, he practiced for the first time diving into the water, a dangerous maneuver for someone who is blind but important toward improving his time.