Megumi Yokota was just 13 when she was disappeared without a trace while walking home from school in her seaside village in central Japan.

Key points: Megumi is one of 17 Japanese people kidnapped in the 1970s and 1980s by spies

Megumi is one of 17 Japanese people kidnapped in the 1970s and 1980s by spies North Korea says she is dead, but her family insists she is still alive

North Korea says she is dead, but her family insists she is still alive Prime Minister Shinzo Abe is prepared to hold talks with Kim Jong-un about abductees

It was a seven-minute walk from the badminton courts where she had spent the afternoon, but Megumi never made it to the house.

Her brother Takuya remembers that day in 1977 well.

"Our house was near the Sea of Japan and the rumbling of the sea was loud, the sky was completely dark and it was scary for children, it was this really dark image," he said.

When Megumi failed to return, her mother went to the school, but badminton practice was over and nobody was there.

"We searched for her in the dark with a flashlight in an abandoned hotel and forests, but there was no trace of her. That's how our 41 years of suffering started."

Police were called and they launched a full investigation, but a sniffer dog lost track of her scent at a street corner just 100 metres from her family home.

"She was so curious and energetic … my brother and I always thought of her as a sunflower as she was such a bright girl," Tayuka said.

Megumi (centre) went missing from her seaside village in Niigata in 1977. ( Supplied: Yokota family )

"When she suddenly disappeared, it became very dark in the family and there was no more conversation. We felt very depressed every day."

Police thought she may have been kidnapped for ransom, but no demand for money ever came.

The Yokota family did interviews on national TV holding up photos of their daughter for the cameras, but no one had any information.

Megumi had seemingly vanished into thin air.

"I always thought of her as a sunflower," Tayuka Yokota said. ( ABC News: Yumi Asada )

It would be two agonising decades before her family found out what had happened.

In 1997, a Japanese government official rang the Yokotas to inform them that their daughter had been kidnapped by North Korean agents.

A former North Korean spy who had escaped to South Korea had reportedly spoken of a young Japanese teen who had been snatched while walking down a coastal road and bundled onto a waiting boat.

Suddenly, hope returned to the Yokota household.

Megumi's strange new life in North Korea

It is believed Megumi was forced to help train North Korean spies pass as Japanese citizens.

She is one of at least 17 Japanese citizens who were randomly abducted by agents from the North throughout the late 1970s and early 1980s.

She became the face of the tragic abductions — an issue that still passionately resonates among Japanese people to this day.

The Yokotas believe the woman in this photo is Megumi, but they are not sure when it was taken. ( Supplied: Yokota family )

Five of the abductees have since returned to Japan, but the fate of Megumi and 11 others is unknown.

At the first ever summit between Japan and North Korea in 2002, then North Korean leader Kim Jong-il admitted to the practice of abductions.

But Pyongyang has claimed that Megumi Yokota took her own life in 1994.

Her family refuses to accept that.

"We couldn't believe it at all. My sister was not the type who would take her own life," her brother Takaya said.

The North returned ashes that were supposedly Megumi's, but DNA tests in Japan proved otherwise.

"The DNA test in Japan found out that it was bones from a completely different person. We knew it was a manoeuvre by North Korea," Takaya said.

"This wasn't just abduction. North Korea took someone else's bones and [committed] a double crime."

It has been confirmed that Megumi married a fellow abductee from South Korea and in 1987 the couple had a daughter, Kim Eun Gyong.

Megumi has a young daughter called Kim Eum Gyong, who met her grandparents in 2014. ( Supplied: Yokota family )

Megumi's parents Sakie and Shigeru met their granddaughter in Mongolia in 2014.

They said at the time the meeting her was "like a miracle".

But they did not talk about Megumi's supposed death as they did not want to discuss difficult political issues.

Sakie and Shigeru Yokota have been tireless campaigners for the plight of the abductees.

They have travelled to more than 1,400 events, gathering more than almost 13 million signatures to try to save their daughter and the other victims.

Shigeru and Sakie Yokota have been fighting to get their daughter back for decades. ( Supplied: Yokota family )

But as they age, their chances of ever being reunited with their daughter diminish by the day.

"My father has been hospitalised since April last year. He's 86 years old and we're at a critical moment as to whether my father would be able to see Megumi," Takuya said.

"Our parents' generation is running out of time and North Korea should immediately stop its human rights violations and hostage diplomacy."

Yokotas hope for breakthrough during Trump visit

Shinzo Abe has met regularly with the families of abductees, including the Yokotas in 2017. ( Reuters: Toshifumi Kitamura )

Japan's Prime Minister Shinzo Abe has made resolving the abduction issue a keystone of his political career, but he has yet to set up talks with Kim Jong-un.

Until this month, he refused to consider meeting the North Korean leader without the promise of significant progress on the kidnappings.

Now he is prepared to meet unconditionally.

Professor Jeff Kingston from Japan's Temple University believes this shift marks the right approach.

"There's really little that Japan can do about the situation on the North Korean peninsula, however Mr Abe has not really put Japan at the negotiating table," he said.

"He has in a way marginalised or isolated Japan by emphasising the fate of the abductees over denuclearisation of the Korean peninsula."

So far, Kim Jong-un has given no indication that he is willing to meet Shinzo Abe.

But the families of abductees are hoping US President Donald Trump may be able to open doors and potentially pave the way to progress on this traumatising issue.

When Mr Trump visits Tokyo this weekend, he will again meet the families of abductees.

Donald Trump met with the Yokota family during a trip to Japan in 2017. ( Reuters: Jonathan Ernst )

The Japanese Government is sparing no expense to please the US President during this visit.

He will be the first foreign leader to meet the country's new emperor.

He will have ringside seats and present a cup at the Summer Grand Sumo tournament, and will make a trip to the country's biggest warship as part of this state visit.

On Monday, the pair will hold a summit and are expected to discuss North Korea as well as China's economic and military rise.

While substantive policies may not arise from this summit alone, it will lay the groundwork for major progress on both trade and North Korea in the future.

Takuya Yokota will be watching the summit closely as he fights for his sister's freedom.

"I think she imagined many things in her life: going to high school, going to university, what job she wanted to do, getting married and having a child," he said.

"Those dreams and wishes were deprived against her will in a violent way."