Tip #90: Practicalities of irresistibility

in your query letter, you want to make the reader believe that all hell is about to break loose--and then leave them dangling, with no idea of how it ends. This should effectively make them frantic to read the book itself. (Note that when I say "all hell is about to break loose", that can also mean a quiet, internalized hell. Introspective novels also focus on escalating conflicts, but the conflict can take place inside the protagonist's head or heart.)

http://querygoblin.blogspot.com/2011/02/query-writing-craft-part-1.html