I know that it probably seems like we demand a lot from queries. Take your xx(x),000 word novel, synthesize it into a few paragraphs, add a little marketing/pitch overtone, highlight your hook (if you've got one), and just send it right off. No problem, right? Eh-heh. The good news is that the query system--while not perfect--does actually work really well. The bad news is that I've got another item to add to your query checklist: character.
It's easy to make your query all about plot: When a shipment of dynamite falls from a B-757 over the city of Chicago, igniting a massive explosion that demolishes the city and spreads into a Midwestern apocalypse, it's up to Jimmy Smith to stop the chaos before the world ends. Sounds like possible blockbuster foil for the movies, but how does it fare as a one-sentence query? If demolition, dynamite, 757s, and apocalypses are your thing, not bad, I guess (if we ignore the leap of faith that takes us from the Midwestern apocalypse to the end of the world and the implicit assumption that the reader is fascinated by the end of the world). But this query would be a lot stronger if we knew more about Jimmy Smith. Why is he the one who has to stop the impending destruction of the world? Who made him Atlas? Is he a reluctant or eager hero? What's his personal motivation to stop the end of the world? What are his stakes?
Those are more questions to answer than you'll likely have room for in your query. However, they're all designed to make the query reader care about your protagonist. If your protagonist goes through the worst tribulations the world can offer, it's all for naught if the reader doesn't empathize with her. So, give us a clue in the query letter as to why s/he's special and why the plot is unique to her/him.