The past perfect tense always refers to something that has happened and is completed at the moment of speaking. It differs from the other tenses of the past in that the action, process or state is completed not only before the moment of speaking, but also before something else that was completed before the moment of speaking. That is why the past perfect tense is sometimes called the "past in the past".
Sein Vater war damals schon gestorben.
Bis 1969 hatte noch kein Mensch den Mond betreten.
Nachdem sie die Kinder dreimal vergeblich gerufen hatten, machten sie sich Sorgen.