Terralux

On a sullen and wintry night of December 1923, the Luxor family line was terminated by the Order, a group of radicals set on a transfer of power.

When actually, that's only what had been written in the history books.

Princess Aurora, the seven-year-old daughter of the reigning queen of Terralux, was the only survivor that night. Forced through the Link, a passage to the surface world, Aurora discovers that Terralux, her home, is really an underground civilization unknown to those on the surface.

Almost a century later, Lily Luxor is alive.

A New York teen, she knows drama like the back of her hand. But she's not up for Broadway. Lily is an artist and has always been one. After creating a series of drawings that she cannot explain, it takes the help of a new friend to piece together the story that lies within each stroke of her pencil. It's from this same friend that Lily is faced with the revelation that she is the only living heir to the Luxor throne, and a key player in stealing it back from Wendell Griffin, the self-appointed king of Terralux.
But security forces are being tightened in the underground city when Wendell catches word that the Luxor line is still intact. The fact that his son, Raphael, has gone missing doesn't do much to help Lily's case, either. She finds herself trapped; her only hope of returning home becoming a new passage being built by the Lux rebels. Missing on the surface, wanted underground, she has to find a way to prove the treason committed by Terralux's king and recover the throne, but also get back home without revealing Terralux's existence.
Whether she wants to be the new monarch or not is not important. She'll handle that if she gets that far. All that matters is the unspoken duty to fulfill a century-old wish. She must avenge Terralux, or the Luxor family line will finally die with her, Griffin's injustices lost forever in time.