Let's try some different lengths.
Twitter hook, 140 characters:
Slave girl Girn'ash will risk it all to free the enemy warrior she loves. Queen Ev'ora wants him for her harem. Everybody is a dinosaur. #SF
Twitter hook, 236 characters:
A shrewd and secretive slave girl in an ancient dinosaur civilization falls in love with a dashing military prisoner, risking both the lustful rage of her Most Potent Chieftess and the threat of nuclear annihilation to set him free. #SF
Query letter hook, 157 characters:
Love and violence, war and lust, secrets and betrayals — even intelligent dinosaurs fell victim to such destructive impulses, more than 67 million years ago.
I welcome imput on any of these. :)