We all know the first line of a query is your "hook." I call the last line the "sinker." You want it to punch them in the face, in a nice, friendly kind of way that makes them unable to forget you after having read the 300 other queries in their inbox. Also, at the end, I'm going to tell you what I think your story is about, based on your query. I know how hard it is to get your ideas across succinctly, and how easy it is for your author's brain to fill in the blanks and not see the gaping holes that the average reader may very well fall into.
Also, for my brave Saturday Slash volunteers I will gladly do follow-up slashes (each more kindly than the next) on your query if you post them on the Query Critique board over on AgentQuery Connect. You'll get advice from me, and also people who are smarter than me. If you do post on AQ, be sure to follow the guidelines and let me know you posted so that I can follow up!
And now for our next brave soul. For clarity, my comments are in yellow.
Superpowers have not changed the one thing Jimmy Ranfaz hates; he is still average. Congratulations, I love the hook. Well done.
Jimmy, a daydreaming teenager from Earth, has always been ordinary at everything. When the tree-descendant I think you mean "descended" super-powered people from Ulfitron pick him to be their new saviour, he believes he finally has a chance to be special. Apparently being the doppelganger of their previous hero makes him powerful enough to stop a returning nemesis, Enshreto, who wants to annihilate the Ulfitronians. Okay, the first thing I'm noticing is that there are a lot of names being tossed around. Yes, I get that you need some of them but you might not need all. Basic query rule is that you don't name a character in the query unless you mention them at least twice. You can get away with "returning nemesis" without throwing the "Enshreto" out there and gumming up the brainlines.
He begins training in psionic abilities on Ulfitron only to discover that he is average at handling them as well. Is there any reason why he should be better at them than anyone else? So he's the previous hero's doppelganger, but does that actually *mean* anything other than physical appearance? An attack wipes out almost everyone he knows on the planet and his frustration mounts when he is forced to team up with the only other survivor, Juvall Spelding. A powerful Ulfitronian, his disdain of Jimmy's limited abilities is only outstripped by his determination to save his people. Um, does he have any left?
When they learn of an even bigger invasion Wait - there's a bigger invasion than the one that wiped out the entire planet except for two people? looming, their only hope of saving Ulfitron lies in tracking down the legendary trees, I'm assuming these are not normal trees? Like, if they popped down onto Earth they wouldn't be totally mesmerized by a bunch of saplings, right? which hold unparalleled knowledge of the universe. Cool, this is how they're better than average trees, got it. But how does having knowledge of the universe help them against the bad guys? But within the journey lies a deep deception; one which reveals Jimmy’s own true origins and forces him to question his loyalties. With time running out, Jimmy must decide where his priorities lie; the heroism in attempting to save countless people or pursuing limitless power to finally rise above mediocrity. Oh, nice sinker.
EVOLUTION: THREADS OF CONTROL is a 90,000 word YA high fantasy novel with a scientific flavour and is stand-alone with series potential.
I think you've got the hard part done - your hook and sinker are awesome. But you definitely need to iron out what you're going to put in the middle. Lots of questions are raised here, and you've got to convince the agent that you know the answers and aren't just relying on authorial convenience.
First - so Jimmy is the previous hero's doppelganger and that's why the tree-people pick him. Is there a deeper power at work here? (I'm assuming yes, because of his "true origins). Otherwise, this feels a little farcical, almost King Ralph-esque. I feel like we're going to get a lot of good giggles during a slightly goofy adventure. But it doesn't look like that's how you want this to play, so I'd reconsider the phrasing of how you introduce the idea of Jimmy. Sure, so maybe they DID pick him because he's the previous guy's doppelganger, but the way it's phrased right now it feels like the opening to a comical MG Sci-Fi.
Second - Jimmy is their hero because he's the old hero's doppelganger. Got it. But... if simply by being the doppelganger he's automatically powerful enough to destroy the tree-people nemesis, how has he 1) never discovered this? 2) been so average his whole life? Are his powers only activated when he's not on Earth? Clarify this.
I'm assuming that there is more than one planet with the tree-people, or a whole universe full, or something like that, because it looks like all but the Juvall fella get wiped out in one swipe, yet he still wants to save "his people." Clarify that.
And finally - the big atomic bomb at the end of the tunnel is cosmic knowledge. Cool. But how is that going to help them win their big battle?