JINAN, June 16 -- Guo Gangtang has found himself under the media spotlight after the success of a film based on the 18 years he has spent riding a motorbike around China in search of his missing son.

"Watching the movie, I cried in silence in the cinema as I relived my journey," Guo said on Monday night, as "Lost and Love" was nominated for a number of awards at the Shanghai International Film Festival.

Attending the festival represented a rare break in Guo's travels. He has covered nearly 400,000 km by motorbike, carrying a messenger bag full of flyers and with a flag bearing a picture of his son strapped to the back.

"It is only when I'm on the road looking for him that I feel like a father. I can't stop because I can't let my son down," said the 45-year-old farmer from Liaocheng City of east China's Shandong Province.

In September 1997, Guo's two-year-old son was abducted by an unknown woman when he was playing near home.

More than 500 people searched for the boy in nearby bus and train stations, but no clues were found. It seemed he and his captor had vanished.

However, Guo didn't give up hope. He magnified his son's photo and had it printed on a flag with the message "Where are you, my son? Daddy will take you home", before embarking on a bitter search through the world's most populous nation.

Guo has left his footprints in 29 provinces and cities, and worn out nine motorbikes. The school dropout even learned to use the Internet to hunt for clues, and printed 80,000 letters to seek help from relatives, friends, volunteers and police across China.

He has burned through all his savings and built up debts of more than 200,000 yuan (about 32,700 U.S. dollars). So when he arrives in a new place, he has to find part-time work to cover his travel expenses.