The full moon pierced the clouds that night, sending rays of light into cracks and sections of the camp. A full moon, a cold day in December. Nobody expected the scream that night.

Most of the senior campers were home, or the ones that had homes. Nico di Angelo lay in his cabin still awake when he heard the scream, when his heart sunk from the pain buried deep within it. He knew that pain, he had felt it before. The pain of fear, the pain of terror.

"Will, wake up." Nico shook his boyfriend awake as he reached for his sword in the dim light. "Something's wrong."

"Nico, the sun's gonna be up in...in four hours..." Will buried his head in his pillow. "Let me sleep for four hours."

"Will! Something's wrong with a camper and they might need you! Are you going to go heal them or not?" Nico threw his jacket on before getting Will in his coat. "Let's go, you sack of potatoes!"

Will stumbled to his feet with his coat hanging off of him. "Lead me."

Nico grabbed Will's hand and ran from the cabin, keeping his sword out and at the ready. He looked around, tried to find anything abnormal. Everyone seemed to be asleep and all the lights were off, except for the blazing lights of the infirmary.

"There." Nico's breath escaped his mouth in a wisp of smoke in the winter night. "Come on, Will." They ran for the infirmary, pushed open those doors to find a scene that neither were expecting.

Two children of Apollo, one child of Hecate. Will's younger brother was on his knees, his hands in his hair and his head to the floor. He was sobbing, taking breaths as if each one was his last. The other child of Apollo was kneeling beside him, trying to calm him down but to no avail. The daughter of Hecate was on the bed, barely breathing.

"What's going on?" Will was suddenly awake as he shot into the room. "What happened? Who's the patient?"

"Will, thank the gods." the more stable Apollo kid looked to meet her brother. "Jesse...he...he couldn't heal her. He couldn't help."

Will moved towards the daughter of Hecate. "What happened to her, Lethia?"

Lethia kept her hand on her brother's shoulder to help comfort him. "H13MB."

The color drained from Will's face. "Again?"

Lethia nodded. "Jesse was going to help try and slow it down but...something happened."

"Hold up." Nico held his hands up in surrender, having put his sword away. "I'm barely following this. What's H13MB?"

Will moved his hand to the daughter of Hecate's head, feeling the soul within her. "Something demigods have seen out of about five Hecate children in written records. This will be the second in the past ten years. H13MB is...is Hecate kids unintentionally mutating their bodies with each spell until almost all of their cells are cancerous. We try to warn them but they never take it seriously."

Nico closed the Infirmary's door before kneeling in front of Jesse. "Hey, calm down. Just because you couldn't heal one person doesn't mean it's the end of the world."

Jesse looked up at Nico, tears pouring from his eyes. They weren't sky blue as they had been the last time Nico saw him, but such a dark blue they were bordering on black. "I couldn't heal anyone today...something isn't right..."

"Will will help you," Nico promised. "Just let him help the Hecate girl and he'll be right over."

Nico moved his hand to Jesse's shoulder when Lethia went to help Will, frowning at the darkness he felt within him. "Jesse...has something changed lately? Did you get on someone's bad side?"

Jesse shook his head just as a terrified shout escaped Lethia. She looked down at her hands, tears welling in her own eyes. "Why didn't it work?!"

Will turned to look at her, his eyes narrowed. "You can't heal either?"

Lethia shook her head. "I was going to help you...all I did was try to help you..."

"She touched Jesse." Nico quickly cut in. "Maybe it's something that spreads. I have no possible idea why or how, but just incase, Lethia or Jesse don't touch anyone. Just for now."

"Where do you get off telling me what to do?" Lethia argued. "You're a son of-"

"Okay, that's enough!" Will's voice pierced the air louder than he had intended. "Lethia, did any of this happen before you touched Jesse?" She shook her head. "Jesse, when did this start for you?"

Jesse looked up from his crying mess of a condition, his eyes taking Will aback. "I just noticed the healing thing tonight. But I've felt different since...since yesterday, I think. After I took a walk in the woods. There was a deer hurt and I tried to help it."

Will and Nico exchanged a glance before Will moved to a stack of medical supplies. He threw gloves at each of the Apollo kids before also giving them a medical mask, his face serious. "We can't let this spread. We have to take precautions and talk to Chiron in the morning. About three and a half hours until the sun rises. Do you two think you'll be good until then?"

Lethia nodded, a small movement, while Jesse went back to crying. Will moved to Nico and whispered in his ear, whispered low enough to not be overheard. "I've got to go fill my cabin in. Go talk to Chiron?"

Nico looked to Will, not moving near his ear but keeping his voice low. "You think they'll be fine by themselves?"

Will shrugged before leaving the Infirmary. Nico was more hesitant but did as he was told, shadow traveling to the Big House's front porch. Chiron could solve this, Chiron could do it.

He knocked, a sound that rattled over the haunted night.