Sipping iced coffee and smoking a cigarette outside a cafe in his hometown, Lin Yi-lin appears relaxed.
But the 41-year-old, locked up for nearly 14 years in China for spying, still suffers a roller coaster of emotions.
After his arrest in 1994, his wife divorced him. His father died of a stroke on a trip to see him in prison. Lin did not even recognise his hometown when he was released in 2008.
But he says: "My biggest regret is I wasn't there during my two sons' childhood. I couldn't play ball with them, or go to their graduation ceremonies. They are grown now. There's distance between us."
Unlike the spies of Russia and the US, Lin and many other Taiwanese spies were not professionals.
They were targeted by Taiwan's Military Intelligence Bureau in the 1980s, when Taiwan started allowing its people to visit mainland China.
Businessmen were the first to go into China - driven by their desire to trade and make money. They developed contacts, sometimes with high-ranking Chinese generals, who were eager to go into business.
"It started when an undercover agent approached me at a party. He introduced himself as a journalist and said his newspaper needed information on China," said Lin, who was running a tile-making business in China at the time.
"It wasn't until later that I realised I was working for the military."
Motivated by generous financial rewards and loyalty towards Taiwan, Lin and others gathered information about Chinese military affairs.
Some of their work was as simple as pretending to be tourists and taking pictures outside military compounds, or reporting a military drill when they saw tanks on the streets or airports temporarily closed.
And, as in Lin's case, it could be as risky as using his contacts to gain access to a military base and taking pictures of Chinese submarines.
"They paid me NT$50,000 (US$1,500; £960) a month, paid for my plane tickets and once gave me a bonus of US$5,000 when I found the submarine base," said Lin.
"After a while, I felt that this is fun. I'm pretty good at it. I can do some good for my country and it's challenging."
But Lin and the others were not trained, although he learned to decipher coded messages and send faxes using invisible ink.
Over the decades, many were arrested, and usually sentenced to more than 10 years in prison.
Taiwan's government refuses to reveal how many of the amateur spies have been jailed, but legislators contacted by desperate families believe several dozen are still serving time in China's prisons.
For the families, it has been a nightmare.
"They are not allowed to visit their jailed relatives often. Many of the families have given up on them," said legislator Justin Chou.
"Some of the people jailed are ill, and others have died in prison because the living standards and medical care are poor."
Many of the families, including Lin's, had no idea their loved one was spying.
When spies are arrested, no one is informed, because there are no official ties between Taiwan and China.
It is only when the spies are sentenced and Chinese newspapers report the cases that the families find out. Some cases are not carried in the media.
The sister of a woman who was arrested in 2007 with her husband said she thought the pair were doing business in China. Since their arrest, she has been taking care of her sister's youngest son.
"All I know is I promised her 10 years ago that I would look after her kids if anything happened to her," said the woman, who wished to remain anonymous, for fear of jeopardising the possible early release of her sister and brother-in-law, who is in his 70s and seriously ill.
She has visited many government offices in Taiwan to seek help.
"What we can't accept is that we've been forgotten by the government. The government's attitude is to throw you away after using you," she said. "This is shameful."
In a statement, the Military Intelligence Bureau said it has tried to help the families with financial support, as those arrested are often the family breadwinner, and by working through unofficial channels to persuade China to release the spies.
"The families really want us to save their relatives, but our ability is limited," a Bureau spokeswoman said.
Mutual intelligence gathering still goes on but businessmen are no longer recruited, she said.
Tensions have run high between the two sides since 1949, when Taiwan was separated from China at the end of a civil war.
But an unprecedented warming in relations since Taiwan's President Ma Ying-jeou took office in 2008, has given the families new hope of formal talks for release on humanitarian grounds, or a spy swap.
But the timing is not right, said the Bureau official and the legislator Mr Chou.
"Taiwan's government doesn't want to formally raise this issue [with China] because it's very sensitive... We don't want to harm cross-strait relations because of this issue," said Mr Chou, who is from the ruling Kuomintang party.
When Taiwan's representatives tried to raise the issue in unofficial channels, China has not expressed interest, Chou and others said.
Still, he and others are working behind-the-scenes to secure early release for those who are seriously ill. A couple of spies were recently freed on medical parole.
Lin and the families of those in prison say they cannot understand why a group of ordinary people, who were simply caught up in the politics of the past, cannot be released.
"These people are not criminals. It's only because the Kuomintang and Chinese Communist Party had different political systems that there was spying going on. These people were not trying to overthrow the Chinese government," Lin said.
Rice and water
He is now fighting to help those still imprisoned.
"So many people helped me... I want to fight for the human rights of the others, so that my tragedy won't be repeated."
In the jail where he was detained in southern China's Fujian province, one of his eight fellow Taiwanese inmates has already died.
Lin was able to shorten his 20-year sentence by earning "points" for early release by working on the prison production line.
Fed mainly on rice and water, those older than him did not have the physical stamina.
"I told myself I have to get out alive," said Lin.
Besides lobbying human rights agencies and seeking reparation from the government, Lin is trying to get to know his sons.