Thirty-year-old single dad, David Lucas, has taken up running as a therapeutic release from watching his wife die of cancer. When he sets out on his regular morning run to tackle the worst fog the Fens have experienced for many years, he is unaware that his life is to change in a way he could never have imagined. And when tragedy strikes, a chance encounter with ex-Olympic runner and coach, Charlie Greaves, presents him with the opportunity of a lifetime...