Descent Into Madness

Brilliant young inventors Oliver and Sienna have always been drawn to the unknown, their minds restless with the need to create, to push boundaries, to uncover what others fear. But when their latest experiment leads them deep into an abandoned laboratory, they realize too late that some mysteries are meant to stay buried.
Something lurks in the shadows-watching, waiting. The deeper they venture, the more the lines between reality and nightmare blur. The facility holds secrets of its own, whispers of past experiments gone horribly wrong, and horrors that refuse to die. As the walls close in and their minds begin to fracture, Oliver and Sienna must confront a terrifying truth:
The greatest battle they face isn’t just surviving the horrors that hunt them.
It’s surviving their own descent into madness.
First in the Insanity series, but can be read as a standalone.