1. Episode 1

In 1988, the families of those on board flight Pan Am 103 learn that the plane has crashed over Lockerbie, Scotland, killing 270. A terrorism investigation begins.

3. Episode 3

A Libyan double agent provides the evidence needed to bring the two suspects to court. The trial gets underway, but a key witness changes his story.

4. Episode 4

A shock verdict leaves the families unsatisfied. Doubt is cast on the court's decision, and 34 years after the bombing, a new suspect is taken into US custody.