In 1988, Pan Am Flight 103 exploded over Lockerbie, Scotland, killing 270 people, the deadliest terrorist attack on American civilians before September 11. Abdelbaset al-Megrahi, a Libyan intelligence officer, was the only person ever convicted for it. This film reconstructs the case that never got its second hearing: al-Megrahi dropped his appeal shortly before being released from a Scottish prison on compassionate grounds in 2009, dying of cancer in Libya three years later. Investigators, lawyers, and journalists go through the evidence that appeal would have tested, including the disputed timer fragment used to link the bomb to Libya and witness identifications that were later called into question. The film lays out the competing theories that have circulated for two decades, from Libyan state responsibility to alternative suspects tied to Syrian and Iranian-backed groups, without settling the question outright. What emerges is less a solved mystery than an unresolved one, still argued over by relatives of the victims on both sides of the Atlantic.