Which is correct to use in the following example, simple past or past perfect?
- We were completely in the dark after the wind blew the candle out.
- We were completely in the dark after the wind had blown the candle out.
The past perfect construction is used to describe a past event that precedes another past event. In the example, the first event is the wind blowing out the candle, and the second event is the speakers finding themselves in the dark. That makes the second sentence an entirely appropriate way of saying what happened.
The crucial word that indicates the sequence of events is after. First one thing happened, then another. The problem with the first sentence is that the use of the past tense in both the main clause and the subordinate clause suggests that both events have the same time reference. If that is what is intended, then it makes more sense to join the two clauses not with after, but with when:
'We were completely in the dark when the wind blew the candle out.'
You would use "had X" when describing and action further in the past before this event, as in: