该剧讲述了Episode 401 : Sidney Chambers attends a talk by the Reverend Nathaniel Todd, a key part of the Civil Rights movement in America. During the event, protestors disrupt Todd's speech and release fireworks, causing the audience to panic and leading to a crush as dozens of people try to escape through a locked door. In the chaos, a man is stabbed and killed by an unseen assailant. The murder sees racial tensions spike and Geordie is called in to investigate.
