The series was shown between 1978 and 1980 and dealt with the German occupation of Guernsey, one of the Channel Islands, during the Second World War.

[3] The series also marked the television debut of Anthony Head as a member of the island resistance.

The islanders were chiefly represented by the respected local doctor, Philip Martel (Bernard Horsfall), who struggled to maintain the peace, while the Germans were led by Major Dieter Richter (Alfred Burke), a peacetime academic who was inclined to be lenient on the Guernsey populace, but whose approach was challenged by his more conventionally nasty SS counterpart Hauptsturmführer Klaus Reinicke (Simon Cadell).

A precursor to his role as Bergerac in the detective series set on Jersey, John Nettles played a police detective ordered to work for the Germans and anguished by the conflict between his duty and collaborating with the enemy.

[1] The review on the Screenonline website by Sergio Angelini describes Enemy at the Door as featuring "stories and characters that explore the complex issues of alienation and wartime collaboration in a multi-faceted and surprisingly subtle fashion."