A group of guests gather in a large country house, owned by the dying Lord Warbeck, who wants what is left of his family around him to celebrate what he assumes will be his last Christmas.

The guests are a motley bunch, including Sir Julius Warbeck, Chancellor of the Exchequer, the wife of one of his underlings, the fascist son of the present Lord Warbeck, and the Chancellor's bodyguard. Also present is foreign historian Dr Bottwink, and the traditional faithful butler.

When the first murder occurs, the house is cut off from the rest of the world by a heavy snowfall, and it is left to Sir Julius's bodyguard to initiate a preliminary investigation before contact can be made with the local police force.