US pilot Lt Donald Kerr with his saviors at the East River Coloumn headquarter in Tuyang, Guangdong province. Photo Provided to China Daily

The dramatic story of how Chinese guerillas rescued Donald Kerr, a young US pilot shot down over wartime Hong Kong, will soon be released as a movie. Zhao Xu met with Kerr's son to hear about his father's dangerous journey home.

For Dave Kerr, the discovery of two nails in the wall of a small kiln, or "charcoal cave", in the mountains of Hong Kong was a revelation.

"A charcoal cave is where wood is burned to make charcoal. Only one being used to hide someone would need a blanket as a door," the North Carolina native said. "My father wrote about the blanket in his memoir and although he did not mention the nails specifically, I can think of no other way to hold the blanket over the door except to use nails.

"Finally, there's the proof - proof that my father once spent some of the most memorable days of his entire life in this place, inside this small, round room with fire-glazed walls."

On Feb 11, 1944, Kerr's father Lt. Donald W. Kerr, took off from an airbase in Guilin in South China in his single-engine P-40 fighter plane.

It was 10 months before the end of World War II, and Japan still controlled a large part of China and the Pacific region.

Kerr, who had been sent to China after the bombing of Pearl Harbor in December 1941, was a member of the US Army's 14th Air Force, partly formed from the remnants of the legendary "Flying Tigers" squadron.

His mission was to bomb Hong Kong's Kai-Tak Airport, which had become a Japanese airbase after the city fell on Dec 25, 1941.

"The Allies sent 32 planes, including 20 fighters and 12 bombers," said Liu Shen, a documentary director-cum-amateur historian who has spent more than two decades unearthing the lesser-known wartime history of Hong Kong and the surrounding area.

"It was the fighter pilot's job to protect the bombers. Lt. Kerr had just shot down a Japanese fighter plane when his plane was hit by incendiary bullets and caught fire."

With no other choice, Kerr parachuted. As he later wrote in his memoir, "pictures flashed through my mind like that of a drowning man".

The memoir, which has never been published, is believed to have been written in the days immediately following Kerr's rescue. It was first brought to his son's attention in 1982, five years after Kerr's death at age 62.

"Rather than falling to the ground in Kai-Tak to 'a circle of angry J-boys', my father landed in the mountains to the north of the airport because he steered his 'chute away from Kai-Tak, aided by a southern wind," Dave Kerr said, quoting the memoir.

"However, as he jumped, he was struck by the tail of his own plane, which broke his shoulder. In addition to this were the severe burns he suffered on one leg and on his face in the very short time that he was in the burning plane.

"People who visit Hong Kong today might think it would be very easy to hide in the dense forests in the mountains, but at that time all the trees and bushes had been cleared for firewood. The land was very barren and there were very few places to hide," he said. "When my father landed, he realized that he didn't know which way to run. He also knew a lot of Japanese soldiers were looking for him because he could see them."