My thoughts are in blue, words to delete are in red, suggested rephrasing is in orange.

16-year-old Clark Zhang has been a screw up all his life, What kind of screw up? Like he drinks straight out of the milk jug, or he drives too fast and killed someone? and he knows it. He’s happiest at Westwood Military High School’s library where cadets can’t target him, since he’s only a substitute Second Lieutenant. Awkward sentence, if you're just trying to establish he doesn't fit in well here, I'd find another way to say it. So, when the police seek help from the Student Corps after Security Chief Paul Coleman’s murder? Not a complete sentence / question, roll it into the next line Hard pass. Snitching won’t get cadets to respect him.

Until he got caught falling asleep during an important meeting… Now, he’s Baltimore PD’s new informant, helping the cops navigate the web of lies and secrets knitting Westwood together. Why? Why would falling asleep now make him the choice for this? If it's a punishment I feel like the PD wouldn't exactly want him if he falls asleep at important times

This would ensure Clark’s promotion pending between him and the oh-so-smart Sergeant James Fisher—whose everyone expects to solve the case for spring break — and the respect that follows. However, his efforts might be pointless when Coleman’s killer targets two students, putting Westwood’s future in jeopardy. Not following this very well - I don't really undrstand why students would be expected to "solve" a murder. Maybe help out, sure. But why would the general student body know who the "snitches" are? Wouldn't that undermine their ability? Does the killer actually kill two more students, or just almost? And if Clark doesn't really care / fit / like Westwood a whole lot, what does he care if it's future is in jeopary?

While Clark struggles to find clues, Fisher’s working with the police on virus-infected microchip after finding it. Desperate to catch up, Clark hides security footages pointing at fourteen-year-old John Baxter, risking jail for hiding evidence. Also, making sure that meddling kid isn’t the next victim. Unsure what all of this means, or how it's tied together

When John vanishes, but I thought his actions would keep John from trouble? Clark’s left to deal with the police and nineteen hours before Westwood’s closure. Clark must choose between fighting his way back to the case, despite working under Fisher, to save John, the school, and prove his worth. Or abandon the case of his life before losing his own. Again, not a lot of tension here if he doesn't really love the school or feel like he belongs there. And what's his connection to John? If he really wants to save him and it's important to the plot and the character, they should be friends and that should be evident in the query. Also, is his life in danger? Why? What does Clark want? What stands in his way of getting it? And what will he have to do to overcome it?

Complete at 80,000 words, THE SLUMBERING SLEUTH is a mystery YA novel with series potential. It combines the wimp-smart amateur detective from Kate Weston’s MURDER ON A NIGHT SCHOOL with the character-driven plot focused on the unravelling mystery and the male relationships of Elle Kennedy’s THE MISFIT. It features #ownvoice Asian American experience with a multicultural cast, themes of found family, and unreliable narrators who often do more harm than good. Good closing para, but the query itself needs to tie more plot elements together in order to work.