The Plusquamperfekt tense describes a past activity that took place before another past activity.
Formation:
For transitive verbs (with Akkusativ, eg. to like someone/something) and reflexive verbs(z sich, np. sich treffen):
hatte, hattest, hatte, hatten, hattet, hatten + Partizip II.
For intransitive verbs:
denoting movement or change of state, and the verbs sein, werden, bleiben:
war, warst, war, waren, wart, waren + Partizip II.
For other intransitive verbs:
hatte, hattest, hatte, hatten, hattet, hatten + Partizip II.