The Cave Underneath

What are those sounds you hear at night? Where do you hear your name from? Where are those random names from?
Gabriella's been hearing the voices since before she could remember, but they've been getting louder and more terrifying. She hears screams, war cries, crumbling buildings; she never thought anything of them until now.
Gabriella and her friends go hiking, only to find themselves sucked into an underground city, where a power-hungry tirant is tearing down the town to reach the light of above, where he plans to take over human civilization.
Can Gabriella find the power to stop him, before he destroys the underground completely?

The cover for this book was made by @unflaw who did a great job, thank you so much!