What is the pluperfect tense and how is it formed?

The pluperfect tense helps to add extra information to an account from the past. It refers to events that took place before the events of the story in the past. For example, I went to the concert because I had already bought the tickets/Je suis allé(e) au concert parce que j'avais déja acheté les billets. In this example the past tense is underlined whereas the pluperfect tense is in italics. Here the purchase of the tickets happened before going to the concert. To form this tense, the imperfect form of être or avoir (depending on which it is paired with in the perfect tense) is combined with the past participle of the main verb. Using our example, acheter uses avoir in the perfect tense (j'ai acheté) therefore the imperfect version of avoir (avais) is paired with the past participle of acheter to form the pluperfect.