Spencer's internal struggle with the trauma inflicted by the cave predator and the facility's attempts to suppress the truth and its growing effects.

Spencer and Davis, two potholers exploring a deep cave system beneath Wenley Moor, descend into a cavernous chamber filled with towering stalagmites. Their initial excitement is shattered when an unnatural, …

In sickbay, the Doctor examines Spencer—a traumatized potholer who, post-coma, compulsively draws prehistoric cave paintings, including a reptilian biped with three eyes. When the Doctor kneels behind Spencer to ask …