"What's that?" Kara asked, gesturing to the odd silhouettes charred on the concrete wall of the lab. They looked just enough like people's shadows to unsettle her.

Dr. Young looked up from the thick metal box in the center of the room. She glanced from the reporter to where the other woman was pointing. "Nuclear shadows," she said quickly and glanced back down at the structure in front of her. "Now, did you want to see the core?"

Kara nodded but was still distracted by the wall behind her. Dr. Young unlocked the top of the container and struggled under the weight as she lifted it open. She waved her hand, indicating for Kara to come closer, and she reluctantly obeyed. As she craned her neck to look into the box, she was a bit disappointed to find that the core - the heart of an atom bomb - was only a large, metal sphere. She rocked back on her feet.

"What are nuclear shadows?"

Dr. Young sighed, seemingly annoyed by Kara's lack of enthusiasm over the core. "They're created in nuclear explosions."

Kara's stomach clenched. "What?"

"The intense heat scorches everything around it. But if something is blocking a wall, then that burns instead and leaves a shadow against the wall behind it."

Kara turns toward the wall, her heart beating a terrible rhythm against her breastbone. "Did something happen here?"

Dr. Young crouched down and dropped her hands into the box, gently stroking the metal ball inside of it. "Someone dropped a core five years ago. It went supercritical - killed five people." She turned toward Kara. "I'm having my doubts about your journalism skills if you didn't know that. But -" she looked back into the container and grasped the metal ball between her hands. "I'm sure this story will get you noticed."

"What are you doing?" Kara whispered, watching Dr. Young begin to lift the core.

"I'm showing you the core."

"I don't think - I don't want to see it anymore. I've already seen what I need to"

Dr. Young laughed and shook her head. The dark human-like outlines on the wall blurred in Kara's vision as she struggled to slow her breathing.

"You said this is the first time in five years anyone's seen the core. That means since the accident - that's what you mean. I don't think this is a good idea!" She was backing toward the thick, bulkhead door, but she wasn't entirely sure it would open for her.

"Well then," Dr. Young said and smiled widely, "we better hope I don't drop it."

Kara glanced back at the charred shadows on the wall, the recorder shaking in her grip.