[1] It appeared on the New York Times Best Seller list and has been adapted into a film by Michael Mann in 1983 and as a limited series of comics in 2006.

German soldiers and SS Einsatzkommandos are being slowly killed off in a mysterious castle (the "keep" of the title) high in the Carpathian Mountains of Romania in April 1941.

Theodore Cuza, a Jewish history professor living in Bucharest, and his daughter Magda are brought to the keep by SS Sturmbannfuhrer Eric Kaempffer in a desperate attempt to determine what is murdering his men.

The professor translates a mysterious message written in blood on a wall that uses a forgotten dialect of Old Romanian or Old Slavonic.

Molasar procures his services through deception and false promises, and even puts the scleroderma from which he suffers into remission so he could work for him.

An immortal man calling himself Glenn, whose real name is Glaeken, is a reluctant champion of the ancient Forces of Light.

Rasalom rashly launches himself bodily at his age-old enemy and is reduced to ashes by a single stroke from Glenn's sword.

The film was also adapted into an Advanced Dungeons & Dragons compatible ("generic universal") module, The Keep, by Mayfair Games in 1984.