The key to solving the toughest homicides lies somewhere in the final hours of a victim's life. In each one-hour episode, determined investigators must piece together events during this critical window to reconstruct the timeline, unlock the motive, and ultimately close in on the killer.

One for the Road follows Jimmy, Paul, Richard and Mark who meet on a rehabilitation course for drink drivers. Jimmy is young, ambitious and desperate to sell his late father's business; Paul has been salesman of the year three times running, however, that was five years ago; Richard is a retired millionaire property developer and Mark is a taxi driver with a weakness for weed and philosophy.