Paul Callow (Mackenzie Crook) is fed up with city life and driving trains and when two people fall under his train in as many weeks he really has had enough! Then he hears the three and out rule - three fatal accidents in a month qualifies you for early retirement with 10 years' salary - lump sum! Paul suddenly sees a way of clearing his debts and escaping to a better life and all he has to do is find a willing victim. Enter down and out Tommy Cassidy (Colm Meaney) who is willing to help Paul out by being his third fatality but not before he ties up a few loose ends with his long suffering ex-wife (Imelda Staunton) and his beautiful daughter (Gemma Arterton). Over the course of the weekend relationships between all four are changed forever but when Monday morning arrives Paul and Tommy are confronted with the harsh reality of the deal they struck. Surely they won't go through with it. Or will they?