Vampires Vs. Aliens, Book Two: Rebellion! - Vampires Vs. Aliens, #2

They came from a dying world to steal the Earth's water, a scarce resource they need to survive but didn't anticipate resistance from the vampires. The aliens' plan would doom the human race... And with no humans or other life left on Earth, the planet's furtive vampire population would be deprived of its sole food source. Now the vampires must wage a secret war against the invaders while hiding their own existence from the humans. In Book 2:  Rebellion!  Sebastian arrives.
He's a mysterious Elder sent by the Conclave of Elders, who disapprove of Gaunt's decision to handle the alien threat without consulting the Conclave. But Sebastian has his own secrets. Hailey Rumson also arrives in town to start classes at the local college in the fall -- and to investigate her cousin's mysterious death. And a rebellion among the aliens threatens to leave Kevian and Kira marked for death. Vampires Vs.
Aliens, Book 2, science-fantasy, YA, 290 pages.