WARNING: Major spoilers for episode four ahead.

January 31st 2001: Nine months after the trial at Camp Zeist began, the jury gives their verdict, convicting Abdelbaset al-Megrahi, but declaring Al Amin Khalifa Fhimah not guilty. Megrahi’s children scream and cry at the news, while Jim looks dumbfounded before collapsing.

Eight months after the verdict, the world is shaken by news of 9/11 in New York City. Megrahi sees the news while still detained at Camp Zeist, with one guard commenting ‘good luck with his appeal’. In the months after, his appeal was refused, and he’s sent to prison in Glasgow in March 2002.

At a time of racial tensions, he is met with jeers and threats, and placed in a secure unit.

Jim and Jane are now grandparents, with Cathy having a baby girl called Isobel. Jane allows Cathy to use Flora’s old room as a nursery – which hasn’t changed since she left in 1988. Jim is stoic and distant from his family. When asked how he is, he’s dismissive, instead talking about the latest in the Megrahi case rather than himself. Jane tells him to stop.

Guthrie sends word to Jim that Megrahi’s been granted permission to apply for a second appeal. Guthrie tries to speak to a policeman who was part of the initial investigation, but he clams up. He pressures him about evidence tampering, and accuses him of knowing about a cover-up. He responds by saying they’re looking in the wrong place.

Back at work, Guthrie is told to move on as Osama Bin Laden dominates the headlines.

Jim meets with lawyer Roderick McGill to talk about Megrahi’s defence case and asks to visit Megrahi in prison. They agree, and when the pair finally meet, Jim asks him directly if he killed Flora. Megrahi says no. Jim says that he believes the case against him is a sham and vows to help him get it overturned.

Jim meets with Guthrie, offering him an interview, but Guthrie is dismissive, saying that the news has moved on from Lockerbie.

At home, Jane and Jim speak about how the appeal is affecting the family. Jane says the kids barely come round anymore, and he’s grown distant from them. Jane suggests they move to be closer to their children and grandchildren, and away from the memories the house holds. Jim refuses.

Later that evening, he meets with Robert Baer, a former CIA agent who is now an author. Baer claims it was Iran’s “revenge” and the CIA had known about it. He alleges that during Operation Autumn Leaves one of the cassette player bombs made by the PFLP-GC went missing, and he believes it’s the one that blew up Pan Am 103.

Baer claims that two days after Lockerbie, Iran paid $11million into a PFLP-GC bank account, and they had proof that was ignored in favour of focusing on Saddam Hussein invading Kuwait, and therefore the US needing Iran and Syria on their sides. Libya, as a rogue state with proven terrorist links and a leader they wanted out of the way, became the best option.

Four years later, in June 2007, Megrahi’s defence succeed in getting six grounds for referral for an appeal trial. By then, Megrahi is in ill health, which worries Jim as he visits him. Jim also worries that, while there’s evidence Megrahi didn’t commit the attack, there’s nothing to indicate who did.

Guthrie is contacted once again by the cop who bailed on him, who is now out of the force. He pushes for information on classified documents held at Dumfries police station, including a letter from the King of Jordan from Prime Minister John Major, suggesting Libyans are innocent of the crime. But the letter was withheld from being put into evidence at trial.

In February 2008, Guthrie’s exposé is blocked by the government from running under interest of national security, with the lawsuit potentially bankrupting them all. His editor refuses to publish it. Jim urges him to find elsewhere but Guthrie says he can’t, and doesn’t let Jim.

In Scotland, Megrahi has been diagnosed with prostate cancer. When Jim finds out, he visits him, acknowledging it is severe but beatable if he fights it. Megrahi says he doesn’t want to die in prison, the UK and Libya are negotiating a transfer agreement for him to go back home.

However, he’s later informed that a transfer can’t happen unless he gives up his appeal, as ruled by Scottish law. His lawyer suggests he fight for release on compassionate grounds, with doctors certifying if he is due to die within a few months.

Jim leads a new campaign fighting for justice for Megrahi, to the anger of political leaders including David Cameron and Hilary Clinton.

On the 20th anniversary of the bombing, families head to Lockerbie for a memorial, and Jane gets angry when Jim wears a new pin badge stating ‘Justice for Megrahi’ – knowing that many involved believe him guilty. She begs him and he takes it off, but that doesn’t stop people gossiping, ignoring and being rude to him at the service.

Jim and Jane argue about what his fight means, with Jane arguing he’s doing anything he can to avoid the grief of the loss of Flora, and he’s missing the life that’s around him as a result.

Megrahi is visited by Libyan representatives, who tell him there’s no way he’ll leave prison unless he drops his appeal. And he needs to make a decision.