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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.
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Frannie is a teenager struggling with Huntington's disease, often missing school, friendless, scared. Francesca, on the other hand, is a hunter and custodian of ancient magical artifacts. An explanation of what Huntington's is might be in order here. Most people aren't going to be familiar. A line or two will do.
But Frannie and Francesca are the same girl.
It all started the night her father died of the same hereditary disease. Whenever Frannie closes her eyes, she wakes up on the other side of the world as Francesca, journeying through ancient monuments, darting through booby traps and racing against the many villains who wish to use the magical relics for their own gain. So is she in the REAL world when she does these things, or a fantas world?
As Frannie gradually loses her battle with HD, she finds herself traveling across the globe and spending more time as Francesca. You mean physically, emotionally, or mentally? She wouldn't mind being Francesca forever, but her grieving mother and best friend make it hard for her to let go. What would it mean for her to be Francesca forever? That's when she learns of the Cintamani Stone: The ancient wish stone hidden in a secret location in South East Asia. To save Frannie, Francesca must embark on her most dangerous adventure yet. Unless... she is just a figment of imagination in Frannie's down spiraling mind. Good sinker.
THE WISH STONE is a multicultural YA contemporary fantasy, complete at 60,000 words. STILL ALICE meets NARNIA, in which fairy tales and folklore help a teenage-girl's battle against Juvenile Onset Huntington's Disease.
Overall you've got a great base here. You need to get the explanatory notes above ironed out and I think you're in a good place.