Two people have died in the accident and many people have been injured, and Tolin must discover the cause of
the crash while investigating the personal lives of the crash victims. Many of the victims seem to have something
to hide: why has a secretary at a chemicals company stolen computer files, and why is she so desperate for an
envelope to be retreived from her car and delivered to her in hospital. Why did the driver of a delivery van flee the
scene after the accident? Why was Brian on the A4 with his mother-in-law, and how did she sustain fatal head
injuries when her daughter swears that she was wearing a seatbelt? Tolin and Stallwood discover that many of the
crash victims know things that they would rather not become public knowledge. The revelation of what caused the
accident comes as something as a surprise, although there were plenty of clues throughout the first four episodes
as to just what happened.

Meanwhile, Paul McGann features as Richard Reeves, a property developer whose shoulder was dislocated in the
accident, although his driver was more badly injured.  The police use a roadside diner as a makeshift evacuation
centre for crash victims who are not injured. Reeves soon takes a shine to Jane Tarrant (Lucy Griffiths), who works
at the diner and helps the paramedics to reset his shoulder. He returns to the diner the next day, and invites her to
lunch. A visit to an art gallery follows, and Jane soon becomes as infatuated with Reeves as he is with her, despite
the fact that he is much older and married. It is not long before Reeves invites her to travel abroad with him, and she
agrees. However, her life is turned upside down when Reeves' wife confronts her at the train station, and informs her
that Reeves is a fantasist who is always inviting women to go abroad with him, but never intends to go through with
it. A forlorn Jane boards the Eurostar alone, while Reeves is last seen in a board meeting at his company.