1. Episode 1

On 7 July 2005, bombs go off at four separate sites across London, sparking untold devastation and the biggest manhunt the United Kingdom had ever seen.

2. Episode 2

The clues take the investigation from London, to Luton, to Leeds, where the community is left reeling at the news — and the backlash from the media.

4. Episode 4

The police are desperate to find the bombers, but the trail is getting cold. Until a call from a member of the public turns the investigation around.