Kelly (Rose McGowan) is a writer and a skeptic of the supernatural. As a specialist in acoustic physics she uses low frequency tactile sound-waves to debunk reported paranormal activities for her online blog. When presented a new case of a supposedly haunted subway station Kelly sets off to uncover the truth behind the hoax that involves a 40-year-old unexplained suicide.

Her investigation takes her deep into the abandoned station where her skepticism is tested. As Kelly ascends into the depths of the metro's darkness she is confronted by an unforeseen evil. In the vastness, she must face her own haunted memories to find the truth and surface back into the light.