Plotting is like sex. Plotting is about desire and satisfaction, anticipation and release. You have to arouse your reader's desire to know what happens, to unravel the mystery, to see good triumph. You have to sustain it, keep it warm, feed it, just a little bit, not too much at a time, as your story goes on. That's called suspense. It can bring desire to a frenzy, in which case you are in a good position to bring off a wonderful climax.