The killing of Alistair Wilson has baffled detectives for almost 20 years. Just after 7pm on 28 November 2004, the young Scottish banker and father was executed on his own doorstep - shot three times at point blank range in a seemingly motiveless assassination. Despite one of the biggest manhunts ever launched in Scotland by the police, Alistair Wilson's murder remains unsolved. This documentary retraces every step of the case, from the killer's arrival at the Wilson house on a dark November evening, right through to the present police investigation.