On a drizzly December morning, Lee Min-bok kneels on the cold ground near the North Korean border and consults his laptop.
He's scanning satellite weather photos to pick just the right spot for his launch. Satisfied, he and a helper grunt as they load 20 large orange helium tanks into a ramshackle van and then head west.
The vehicle is so laden with gas containers, the chassis bounces with a sick thud atop its struts at each bump in the road. Lee and his partner, Kim Sung-soo, say little, apparently lost in their own thoughts. They have brought a baggie of peeled, browning apples to eat.
Less than a mile from the border, they back the van into the cemetery of a small chapel. One by one, they fill plastic balloons with the hissing helium, creating 36-foot-tall cylinders that snap in the wind and tug hard on the ropes, as if eager to be set free.
Lee, a compact man with thick black eyebrows and a baseball cap pulled low on his head, consults a compass for the precise launch direction, then double-checks his calculations on a map.
He attaches a plastic satchel packed with thousands of vinyl fliers. He sets the timer, and waits for the right wind gust.
The first balloon floats up silently, joining the plodding gray clouds on their easy drift toward North Korea. Lee takes pictures and says a few prayers aloud.
"No one can stop this," he says. "These balloons fly under the radar. No one sees them. They're perfect messengers."
Lee is equal parts meteorologist, tinkering inventor and political dissident, a man obsessed by a singular goal: to spirit messages to those left behind in his native North Korea -- 23 million countrymen living under the ironfisted rule of Kim Jong Il.
To reach the isolated society devoid of outside newspapers, radio and television, the 52-year-old defector uses a simple yet elegant method to fly under the radar of North Korean intelligence watchdogs: He sends millions of leaflets northward by way of his towering helium balloons.
In this high-tech age, the balloons have struck a nerve with Pyongyang and landed Lee and other launchers center-stage in the Korean peninsula's high-wire political standoff.
Last week, North Korea cited Seoul's inability to control the launches -- by defectors and a handful of civic groups -- as a major reason to again close its border, banning tourists and reducing trade.
Tensions between the two Koreas have risen in the last year, especially after the February election of conservative Lee Myung-bak as South Korean president. The administration of Lee, who is a hard-liner on Pyongyang, says it is helpless to stop the launches.
Analysts say the leaflets are written in simple language by former North Koreans who intimately know the North's culture and which political buttons to press.
The vinyl leaflets from Lee, founder of the North Korean Christian Defectors Assn., are often religious. But they also strike at a ruler referred to as his nation's paternal "Dear Leader."
"Dear North Koreans," one begins, taking aim at Kim. "So he's a General who eats rice gruel together with the people? But how could he get love handles and a double chin if he eats rice gruel? People are starving to death, but why does the country spend so much for Kim's [extravagances]?"
South Korean officials are seeking ways to ban the launches, which they say jeopardize the fragile truce between the Koreas.
Many academics agree.
"Shouldn't they stop sending fliers, to prevent inter-Korea relations from being destroyed?" asks Paik Hak-soon, director of the Center for North Korean studies at Sejong Institute in South Korea.
This week, several civic groups said they would hold off on the launches for now, but Lee focuses on the long view.
"People in North Korea are dying every day, with their eyes and ears covered by Kim's regime," he says. "Do we just sit here and watch them die? No matter what they say, we have to do this."
Lee's reverence for his Dear Leader began to unravel in the 1990s, during a horrific famine that killed tens of thousands of North Koreans.
Lee, then an agricultural scientist in Pyongyang, sent numerous letters to the regime, advocating that officials follow China and open the society to outside trade and commerce to stem the starvation.
His letters were ignored, he said. So he quietly planned to defect, divorcing his wife so she wouldn't be persecuted after he was gone. He also left behind a young son.
He first went to China, but was caught and sent back to North Korea and prison. Later, in 1995, he stole across the world's most heavily armed border into South Korea.
Lee spent years adjusting to life in a free society. He remarried and had another child.
Then, in 2004, the two Koreas agreed to halt decades of propaganda warfare, which had involved floating leaflets and blasting loudspeakers across the border.
The truce angered Lee. He decided to continue the launches on his own. He immediately began studying the science of wind.
His first efforts were failures. He bought small party balloons and attached a flier to each. They traveled a short distance before drifting back to earth.
He bought bigger balloons and affixed bundles of fliers. He developed a simple timer that opened the bundles on schedule.
He worked covertly to avoid police. One of his first big launches landed in the Han River in South Korea. Another settled on the lawn of the Blue House, the home of the South Korean president, according to press reports.
But he improved with time. Now Lee and others release tens of millions of leaflets each year into North Korea.
Lee says his messages are not aimed at Kim, but his subjects.
"There is no reasoning with Kim," he says. "He's a god in his own mind. He doesn't make mistakes. But these aren't bombs. This is a peaceful war against Kim Jong Il."
The messages are reaching common North Koreans.
Park Kwon-ha, a defector and former North Korean soldier, escaped in 2005. He says the leaflets were like gold from the sky: "It cannot be overemphasized how effective the fliers are. Because the more you learn from one flier, the more you want to know."
It's not surprising North Korean officials are infuriated by the leaflets.
"Pyongyang is apoplectic," says Marcus Noland, a North Korea scholar for the Peterson Institute for International Economics in Washington.
"These defectors are from within the system. They know exactly what to say and how to say it. And they hit a nerve. For Pyongyang, they stick the knife in and twist it."
Lee knows that he's viewed by many South Koreans as a fringe element who will never achieve his goal of toppling Kim. He prefers to see himself as a North Korean David, slinging leaflets at a mighty, but vulnerable, Goliath.
Lee gets visibly upset as he discusses Kim. He begins many sentences with, "You don't know what it's like in North Korea."
He acknowledges the personal cost of his mission. He thinks of the wife and boy he left behind and he becomes rueful, and then angry.
That's when he starts planning another balloon launch.
Preparing his balloons on the recent rainy morning, Lee pauses to consider an ominous sky the color of spilled ink. He likes what he sees.
"The wind is right," he says softly. "It's blowing toward Pyongyang."
Being so close to the border is an emotional experience for Lee and Kim, his helper and fellow defector. They're so near they can almost smell their homeland. But they focus on their task. Some balloons are attached in pairs, drifting off in the shape of a large V.
The last pair start low, clipping the top of a tree, spilling leaflets before rising into the airstream. Lee sighs. "When one fails," he says, "it feels as though I've lost a child."
Done at last, Lee and Kim watch the sky, spellbound and laughing like schoolboys as they munch on the brown apple slices. Like the balloons, their spirits have lifted.
Lee says the falling leaflets are a beautiful thing to behold. It's like a sprinkling cloud, he says -- a gentle snowfall of fliers falling into the hands of his fellow North Koreans.
Minutes later, Lee is still searching the horizon. Then he sees the last balloons, two tiny pricks in the vast distance.
"Aha!" he shouts. "There they are! They're over North Korea! Go! Go bring the word!"