Investigating the crash of Pan Am flight 103 at Lockerbie in December 1988 which left 270 people dead and became Britain's worst terrorist attack. After a massive police and FBI investigation a Libyan intelligence officer was found guilty of mass murder, but he has now been granted a second appeal against his conviction. Twenty years on, will the full story of Pan Am flight 103 finally emerge? The Conspiracy Files follows the trail of evidence from the Middle East, through Europe and on to North America, investigating the tangled web of claims and counter-claims surrounding the Lockerbie bombing.