Every Day the minds and emotions of Britain's citizens are changed by the coming and going of thirty million letters. This film shows the magic of the mail. A look at some of the familiar and unfamiliar services provided by the Post Office, how it is done, who does it and what they think about it, whether it be a postmen in the Outer Hebrides, a sorter on the postal special out of Euston or an engineer supervising the working of a new automatic letter-facing machine.