Folks, let's talk plot and how it relates to your query letter, because I've seen a mistake repeated a few times recently and heard other writers complaining about the same thing.
Here's the story. Fred is going to work. He meets Wilma. They have their meet-cute and they both like each other.
AND THEN!!! Fred breaks his foot, and Wilma stops by to loan him her crutches.
AND THEN!!! Wilma runs out of milk and goes to the grocery store where she gets a flat tire, so Fred comes over and changes it.
AND THEN!!! There's a thunderstorm that knocks out power to the city, so they can't charge their phones to text each other.
AND THEN!!! A wormhole opens up and Fred has to go shut it to save civilization.
You get the picture. None of the major plot points are related to each other. It's as though the story itself were a bunch of snapshots. Sure, the main characters keep getting together, and sure, they'll probably have their Happily Ever After at the end, but it's not satisfying because none of the events are related to each other any more than the first pitch ("STRIKE!") is related to the second pitch ("BALL!") and so on.
The solution to this is to figure out how to connect your plot points with "And therefore" instead. Fred and Wilma meet and hit it off, and she loves hiking, so Fred pretends he loves hiking too. They decide to meet for a hike.
AND THEREFORE Fred breaks his foot, because he doesn't know what he's doing.
See how this works? When you're reading it, everything seems to flow naturally one from the next, almost as if the events were inevitable. Of course Fred would want to show off and end up hurting himself. Of course Wilma would respond to that with compassion and just a little mockery. And at the end, of course that thunderstorm would open the wormhole, and of course Fred will be willing to climb the skyscraper and shut the wormhole because he's learned from the foot-breaking incident how to be careful and not show off.
In hindsight, all those things will be perfectly sensible. Of course there are plot twists, but not plot twists like, "Oh, and then they got into a huge car crash and everything changed." Not unless you've shown us ahead of time that your MC is a lousy driver who doesn't pay attention, and therefore was texting while driving and hit a truck.
Readers and editors don't like and-then plots, and therefore neither do agents.
And therefore your query shouldn't look like a string of things that happen to a bunch of interesting people.
One of my ex-agents (we shall not name which) accidentally turned out a pitch like that for one of my stories, and I only realized it when we got back a rejection saying, in effect, there's no causation here. Of course in the story there was lots of causation, but in an attempt to work a complicated plot into a 250-word pitch, the agent had in effect listed a bunch of plot points. And then they do this, and then they go there, and then the antagonist does this other thing, and then they have more problems, and then they pull it together somehow.
So we reworked the pitch until it had that sense of rolling inevitability. This happens and they respond by doing that, which has the unintended side effect of this other thing, which triggers a specific response by the antagonist, which results in the following chaos for the main characters.
See how that works?
Oh, and yes, "and then!!" happens all the time in real life. And then you come home to find a notice from the IRS in your mailbox saying you're getting audited because you reversed two digits on your 2011 tax return. And then your kid falls out of a tree and breaks his arm. And then you get a promotion and will have to move to Pensacola. Keep in mind that life itself doesn't make for good fiction, and that people expect the author of their fiction to craft a story that flows toward a climax and a resolution.
And therefore here is your takeaway: when pitching, set up your characters and their circumstances so that as every piece unfolds, the agent will feel a sense of, oh, I see why that would happen, and then Yes, they'd get into trouble doing that, and then Oh no, they're making their situation worse.
Remember, it's not "AND THEN!!! you get an agent." It's and therefore you got your agent. You crafted a wonderful story with a compelling plot and characters who responded believably to their circumstances, and therefore readers loved it.