One quarter to one third of the way through a novel, I sometimes hit this dead spot. I’m not sure where the story is going. For instance, this happened with Building Character (Book 2 of the Northwoods Trilogy).
Instead of a linear progression from one scene to the next I had a beginning and an end, but there was this entire middle part missing. I wondered how I was going to fill it in. There didn’t seem to be much room for story there.
One character was in transit to the location of the other characters and I wondered how I could stall her with more story. A flat tire? I even addressed that a bit by having her break up the 28 hour drive by two nights in a hotel at different points in the trip. But that wasn’t enough. I joked to myself that after 15 thousand words, I could finish the story in a few chapters. I became preoccupied with how to fill in the middle. This is where thinking out of the box is a helpful skill to have. I finally I realized that the missing part of the story might have been AFTER she arrived rather than before.
So I essentially compressed what I had, shoving the ending up against the beginning and then adding the remaining story after that.
Sometimes a story doesn’t end where you initially think it will. You have to be willing to move things around sometimes.