For centuries, war has been brewing below the surface of New York.
People known as the soulless - immortal humans with strange powers - have threatened life on the surface.
The Dark Queen seeks revenge for a crime long forgotten and wants to rule the world.
Eighteen-year-old Riley Stark - a new recruit in the Sentinels, a military group that protects Earth from the Underworld - thinks she's joining for the right reason.
As a child, she narrowly escaped an assassination attempt on her life, and has wanted justice ever since.
After Riley goes snooping through her records, she finds the terrible truth - her ancestor was Mira Stark who killed the famous Dark King, and the soulless have wanted her family's blood spilled.
When Riley falls in love with a soulless boy she's been taught to hate, she realizes that she can't trust anyone - soulless or otherwise.
