 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 2005.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.