Here are some possibilities, depending on the context:
* Allusion: If the "what had happened" refers to a specific event, myth, historical figure, or literary work, it could be an allusion.
* Flashback: If the passage jumps back in time to describe the event that happened, it's a flashback.
* Foreshadowing: If the reference is meant to hint at something that will happen later in the story, it's foreshadowing.
* Suspense: If the reference is used to create tension and keep the reader guessing about what happened, it's creating suspense.
Once you provide the context, I can help you pinpoint the specific literary term.