BBC Ireland correspondent
The story of Tommy McKearney and Billy Mitchell has a brutal beginning, and a happy ending.
Once, they would have killed each other, now they work together.
McKearney is an ex-IRA man, and a former life sentence prisoner. Mitchell used to be in the UVF, and went to jail for murder.
They bumped into each other towards the end of their prison sentences. Now they see each other regularly, at editorial meetings of the magazine they produce together.
They disagree sometimes, but they don't need guns to resolve their disputes.
Unfortunately, both men know all about weapons.
Both men are now working on a cross-community magazine
McKearney was involved in the killing of a part-time soldier, shot dead as he delivered letters on his morning post round.
Mitchell was part of a gang that murdered two men during a feud between rival loyalist paramilitary groups. The men were killed beside two shallow graves which had already been dug.
Sentenced to life, both men ended up serving 16 years. McKearney was involved in the so-called dirty protest while in the H-Blocks of the Maze Prison. He went on hunger-strike for 53 days, and nearly died.
Last month, Mitchell and McKearney went back to the Maze. This time, they were visitors not inmates.
They agreed to take part in a BBC documentary entitled 'Life after Life', and the interviews for the programme took place in an H-Block cell.
The jail is now unoccupied, but the authorities needed a lot of persuasion to allow the two former prisoners back in.
It's a source of regret that the conflict happened, that people in both communities were forced to take up weapons.
In the end, the Northern Ireland Office agreed.
McKearney and Mitchell arrived with mixed emotions - intrigued to see the place again, disturbed by the memories it brought back.
Twenty years ago, no-one would have guessed that McKearney, a fanatical republican, would be back in prison one day with Mitchell, a die-hard loyalist, walking down a corridor like old friends.
But there were serious topics to talk about. Did they regret what they did? How did they respond to the
view that they should have been locked up forever?
And what about their own relationship - can a loyalist and a republican ever trust each other?
Mitchell tackled the issue of regret.
"It's a source of regret that the conflict happened, that people in both communities were forced to take up weapons. But in 1969 someone didn't drive over Northern Ireland and drop laughing gas or crazy gas.
Both men served 16 years at the Maze prison for their crimes
"The seeds of the conflict were here eating away at our society."
Looking over at McKearney, he said: "We were the end product of the malaise that was in our society. So I regret that that happened and that a conflict had to take place."
McKearney added: "I personally have a great understanding of the trauma people go through losing loved ones. Three of my brothers died in the course of this conflict."
One of those brothers was killed by the UVF, the group in which Mitchell used to be a commander.
So do they trust each other?
"I wouldn't work with him if I didn't," said McKearney. Mitchell agreed.
What makes this particularly surprising is that McKearney is a republican hardliner, and unlike members of Sinn Fein, he is opposed to the Good Friday Agreement.
I personally have a great understanding of the trauma people go through losing loved ones.
Mitchell, a born-again Christian and member of the loyalist Progressive Unionist Party, supports the Agreement.
"I can trust Tommy to be a republican, " he said.
"I can't trust Sinn Fein to be republicans. They've converted to Catholic nationalism. Those who fought for 25 years to undermine the British state are now administering British rule in Ireland. I can't trust that sort of republican."
Through the magazine 'The Other View', the two men develop their political thinking. Other ex-prisoners are also involved in the project.
Their efforts were recently marked by the charity Co-operation Ireland, with the presentation of a special award.
Tommy McKearney and Billy Mitchell can never escape their past. Not surpisingly, they prefer to talk about their future.
It's easy to be cynical about their partnership, but at a time when Northern Ireland's politicians seem to be drifting further apart, the coming together of McKearney and Mitchell is a small step in the right direction.
'Life after Life' will be shown on BBC News 24 on Saturday 14 June at 1030 and 1530. It will also be shown at 0430 and 2330 on Sunday 15 June. BBC World will be showing the programme at 2130 GMT on Thursday 19 June.