Sucky Synopsis Sludge

Why is it that I can spin 100,000+ words into a cohesive and entertaining work but when someone asks me what said work is about, the best I can say is, "Uh. I don't know. A church shooting...kinda sorta." ?
This doesn't at all tell what my book is about and I have such a difficult time reducing the story's complexity into a sound bite. After writing various versions of synopsis sludge, I think/hope I have a decent a page and a half. I focused on the main plot of suspense and laced in some mentions of the romance.
Present tense. √
Main characters. √
Story question. √
Main goal. √
Conflict[s]. √
Final resolution. √

Now that I have it done, I want to get smaller. Some agents—none that I'm submitting to but still—want a ten-word hook . So, I've been shrinking my synopsis down to a microblurb for exercise. Tougher than I thought. Do I go for the main goal, concept, story question, the vague deeper meaning behind everything or can I pick a little teaser? I'm not sure.
Some context: Kings & Queens is about a seventeen-year-old who overhears a plot for mass murder in the woods. Unsure if police believe her, she aims to stop the would-be-killers before they act, but they have an agenda far bigger than she ever assumed. Violence rocks her town, leaving residents reeling and pulling her into the middle it all. With danger always pressing, police seemingly getting nowhere and those closest to her looking guilty, she takes matters into her own hands, but the truth and her actions threaten to haunt her forever, especially since she's left with blood on her hands, the blood of someone she loves.
These are my experimental ten-worders.
◊ A teenage girl challenges bloodthirsty killers in a deadly game.
◊ Only ONE can reign, but winning could still cost everything.
◊ When a King chooses his Queen, all bets are off.
In order to get deeper into what my story is truly about, most of my hooks end up looking pretty vague. Do any of them strike your fancy? The first one sounds too YA. I like the second one. It's so hard to pick out the most interesting parts and true meaning of the novel while not giving away the whole plot. Have you worked on a ten-word hook for your long work? Try it if you haven't. It's more of a headache than it is fun, but it's worth the effort.
Hopefully, I can come up with a better face-to-face summary. I'm terrible at it. Cocoa is calling me and so is my manuscript.
~ Signing off and sending out cyber hugs.