The three phases of plot

The simplest way to think of plot is to see it as having three phases:

   Challenge - the problem/difficult event of the story

   Complication  - a series of tests and sometimes traps your characters must overcome

   Resolution - the build up of the story to a final crisis

In Panthera : Death Spiral, Ren's challenge is to find out why whole litters of kingcat cubs are dying.  She agrees to relocate a pair of healthy cubs half-way across human space.  The tests she and her brothers face include defending the cubs against people who want to snatch them, stopping a kidnap, and having to lengthen their journey to twice its original size to keep the cubs safe.  In the resolution Ren and her brothers find out how the man with the strange blotched face who died outside Ren's door is connected to the deaths of the cubs.

The best book I've come across for plotting is Chrisfopher Vogler's The Writers' Journey.  I bought my copy over twenty years ago, and it's still in print today.  It translates Joseph Campbell's work on the structure and themes of myths to a highly useable form for the reader.  

If you're stuck with your plot, I'd recommend you get a copy and look at your story through its framework.