I went into this without reading any of your other queries, so bear that in mind.
In an underwater village on the planet Vis Decor, no species speak as the dark-skinned Greys give their food and labor to the light-skinned Pures. Only one sixteen-year-old grasps this injustice--and this Pure’s innocent call for equality whips her village into a mob.
I feel like you're using too many words in this hook. Would you be able to cut out the stuff about "Greys" and "Pures" and just keep the guts of the story? That Alphi is a sixteen-year-old in an underwater world who speaks up against inequality, causing riots?
I had to read over your older queries to realise what you meant by "no species speak". I understand now that you mean no-one objects to the inequality, but maybe even "speaks out" would clarify this? Then again, the alliteration trips me up a little.
Forced to flee her own home, Alphi’s only refuge is her uncle’s magical city. But even with all its twirling buildings, the city can’t keep her happy, and her joy is shot dead when the President--her uncle-- brutally tortures a Grey. No matter how much she searches, there is no way out --until the Grey rebels attack her own family. And when they do, she joins them.
First you say that the city can't keep her happy, then you say her joy is shot dead. If she wasn't happy in the first place, her "joy" wasn't there to be shot, was it?
Also, you say she's searching... What for? This sentence confuses me. Is she trying to find a way to escape her confusion? The city?
The rebels are the family Alphi longed for, ones who, above all, value her ideas. But the declaration of war sends everyone up in arms, and although Alphi is left crying for peace, she knows only a war can stop her uncle. The line between right and wrong has never been so blurred, and neither of her families will be able to guide her through the bloodshed yet to come.
I like this last paragraph. I get a good idea of the stakes. This is the bit of your query that makes me want to read more.