DCI Ian Forsyth and DS Alistair MacRae are baffled as to why elderly people are being killed by being shot in the head while asleep in bed. They are also investigating the murder of the eldest son of a local landowner and business man. Forsyth is eventually able to work out why the old people are being murdered and to show that the two investigations are related. When a local villain is found dead in the snow in the landowner's garden, MacRae is astonished when Forsyth informs him that he has logically deduced who the killer is but that he has no proof that would convince a jury of the correctness of his solution. But, when he is able to interpret an altered version of the poem 'The Soldier' that was found he villain's car, he realises that he now has the necessary proof.