Our boyish hero, let’s call him Kaoru, returns during the university break to his family home in Niigata, a fishing port on the Sea of Japan. One evening, he leaves for a date with his girlfriend, Yukiko, and the two head for a quiet part of the beach to watch the sunset. Aaaaah.

Kaoru senses something sinister behind him. Creepy! He turns in time to see a man in dark sunglasses approaching him for a light. As Kaoru is fumbling through his pockets, the man punches him with expert precision, just below the nose. Thwack! Kaoru falls unconscious and is stuffed into a giant sack. Yukiko is bundled into a bag alongside him and the two are loaded on to a fishing boat bound for the secretive Hermit Kingdom.

If the story sounds like a comic strip, it is. “Recaptured” is the tale, told in Japanese manga form, of a young man abducted to North Korea, where he is forced to instruct spies in the ways of Japanese language and culture. It is also the true story of one of many such abductions, whose macabre and fantastic details have seized the Japanese imagination.

Until the autumn of 2002, many Japanese considered absurd the claims that dozens of young adults had been plucked off beaches by North Korean agents in the 1970s and 1980s. So when, on October 15 2002, five of the missing Japanese returned to their homeland - brought, as if from the grave, by jet from Pyongyang - the nation was transfixed.

One of the returnees was Kaoru Hasuike, now in his mid-forties, who as a student had been snatched from the Niigata seaside. With him was Yukiko, who never saw the sunset that evening in 1978, but who did become Kaoru’s wife.

The story of these terrible events is related by Toru Hasuike, Kaoru’s elder brother and long-time advocate of the families of the vanished. Toru, a bearded 49-year-old with a grizzled expression, is a household figure in Japan, where he has campaigned for a quarter of a century to have the abduction case taken seriously.

Toru’s mutation into a manga comic, alongside a cast of other real-life characters whose faces appear almost nightly on Japanese news programmes, is as if the Abu Ghraib prison scandal suddenly surfaced in the Beano. The author says he was initially concerned when publishers approached him with the idea of rendering his story, already published in conventional form, into manga. “I was worried, yes,” he recalls. “I told them: ‘I don’t want you to make it funny, or warp the events. I don’t want you to goof around with this.’”

Yet it is not unusual in Japan for manga comics to deal with the most sophisticated or grown-up of themes. Toru is content with the outcome, a 340-page book of black-and-white drawings and speech bubbles, whose brooding tone and taut plotline is more Dostoevsky than Doonesbury. “This is not a comic. It is social documentary,” he says.

His purpose was to bring the story of the abductions, whose treatment by much of the media is more cartoon cut-out than his own darkly psychological version, to a wider audience. “There are generations that read only manga, a layer of people that we can no longer connect with through the printed word,” he says. “I would like to carry my message to those who read cartoons only.”

What is that message? “Recaptured” obeys one of the first rules of authorship: write about what you know. The story deals only in passing with the great diplomatic tussles that the abduction saga has unleashed. (North Korea has sent spy ships into Japanese waters, fired a missile over its territory, and threatened to turn Japan into a “sea of fire” with its nuclear weaponry.) Nor does the story stray far into Toru’s brother’s life in the North Korean capital, Pyongyang, about which little is known. Instead, he relates a personal tale of brotherly separation, divided loyalties and the pain of trying to rebuild a fraternal relationship whose middle 24 years have been robbed by North Korea’s maverick leader Kim Il-sung and then his successor, Kim Jong-il.

At the start of the story, when Kaoru emerges from North Korean exile wearing a lapel-pin bearing the face of the North Korean leader, he initially intends to return to Pyongyang after a brief visit to Japan. Kaoru and Yukiko have been forced to leave their two North Korean-born children in Pyongyang, rendering a second generation of Hasuikes hostage. Even so, Toru cannot understand why his brother would willingly return to the country that stole his freedom.

“We intervened and we made a lot of effort to remind them about what it is like to live in Japan. We convinced them to switch paths,” Toru recalls. “But they had a lot of mental strife. They had to choose between their parents and their children.”

Early on in the plot, the action flashes back 24 years to the night of Kaoru’s disappearance. The two brothers sat around strumming a guitar and drinking beer, before Kaoru borrowed his grandmother’s bicycle and pedalled off for his ill-fated evening with Yukiko.

Toru recalls searching Kaoru’s room the following morning, discovering that his bed had not been slept in, and finding money and a driver’s licence on Kaoru’s desk. The police didn’t take his disappearance seriously even when it was discovered that Yukiko was also missing.

The family scoured the beach front countless times, hired a private detective, and went on a TV programme about missing persons. Once, they received information that Kaoru had been spotted in a pachinko parlour in Nagoya, and Toru spent several days tramping the seedier parts of that enormous city.

“Ten years passed with no clue. People said they had been spirited away or maybe taken by aliens,” he says. “We did not know what to do. We went to shrines and temples and paid a fortune teller.”

No one in authority took much notice, even though strange stories had begun to surface of mysterious kidnappings up and down the Japanese coast. More details began to emerge from Korean defectors, some of whom claimed to have direct knowledge of the abductees. Pyongyang scoffed at Japanese claims, railing at its former colonial master. Only when prime minister Junichiro Koizumi took the extraordinary step of flying to Pyongyang in September 2002 did North Korea finally admit to the kidnappings. All but five of the abductees had died, it said, some in a series of seemingly bizarre accidents.

In the manga version, Toru tries to fathom how his brother can remain loyal, outwardly at least, to a regime that had perpetrated such horrible deeds. Every so often, like a melodramatic camera shot, there is a close-up of the North Korean dictator adorning Kaoru’s lapel.

“He wasn’t really loyal,” says Toru. “But he had to be loyal in order to survive. He had no choice but to act like that. If he’d gone against them, he knew very well what would have happened. He would have been taken to a concentration camp, or killed.”

After Kaoru and Yukiko were kidnapped, they waited to be rescued by Japan, he says. But no rescue effort ever came. “After three years or so they gave up. They gave up on the idea of going back to Japan. They concentrated on living, on surviving.”

Does Toru really know nothing about his brother’s life in North Korea? “They had food. They were paid a salary. They lived perhaps a little lower than a typical middle class family [in Japan]. They were isolated from the rest of Korean society. Because Kaoru was working for a special organisation, he was not really in touch with common people.”

Kaoru and Yukiko were eventually persuaded by their family to stay in Japan, but they spent an agonising 18 months waiting for Tokyo to negotiate the release of their children. Yong Hwa and Ki Hyok, now bearing the Japanese names Shigeyo and Katsuya, finally came to Japan this May, unable to speak much Japanese and largely unaware of their parents’ story.

Several other abductees remain unaccounted for. Last month, Pyongyang shipped back what it said were the ashes of Megumi Yokota, who, as a 13-year-old girl, was stolen from Niigata a year before Kaoru and Yukiko, on her way home from badminton practice. Seven crates were sent back to Japan containing personal effects said to belong to abductees. In the latest of many bizarre twists, when they reached Japan, five were empty, according to the families of the victims.

Toru continues to take a less cartoonish view of events than most of the Japanese media, whose shrill and hysterical coverage has pored over every detail of the abductees’ lives, yet reached few meaningful conclusions about what the entire episode was about. He has started delving into Japan’s history and weighing his country’s occupation of the Korean peninsula against the kidnappings carried out against his own countrymen.

“North Korean people don’t feel guilty about abducting Japanese people. They say: ‘Look what Japan did in the past,’” he says. “Actually, you shouldn’t make a connection between the two. And I am not saying that because of this the abductions were OK. I am not saying that at all. But from a broader perspective, there is a background to all of this. We must think about the roots of this problem.”

Toru’s attempts to grapple with the larger meaning of the kidnappings in the context of Japan’s troubles with its neighbour lurk, half-submerged, in the manga version. Terse conversations with his brother begin to change Toru’s opinion about the rotting bits of leftover history on which the hostage tragedy festered.

Such thinking brings neither him nor his cartoon lookalike much comfort. “Why my brother? That was some kind of strange destiny,” he says. “The background to all of this is country-to-country conflict. And in this conflict, innocent people were sacrificed.”

David Pilling is the FT’s Tokyo bureau chief.