The teens made their way to the Animal Clinic to find out if Deaton had a way to save Mason. Scott and Liam arrived with the Surgeon and told Deaton what they'd found out.
"Mason had a vanishing twin," Deaton repeated.
Stiles shrugged. "Now we've got a vanishing Mason."
Kasia grinned slightly as Liam asked, "What does that have to do with turning him into a 250-year-old French guy? How does that even happen?"
Deaton looked between them. "Hold on, Scott might have something. Mason's twin wasn't entirely gone. That's what made him a genetic Chimera."
"The DNA was still there," Scott realized.
Deaton nodded. "Metaphorically speaking, the DNA of Mason could still be inside Sebastien as well."
"How?"
Lena leaned against a wall. "Think of life as energy, Scott. Energy doesn't disappear. It transfers. What? I know things. I'm not just a nerdy, pretty girl."
Deaton continued. "The Dread Doctors may have found a way to break the rules of the supernatural world, but there are some rules that simply won't break."
Liam was silent for a moment. "So Mason can't just be gone?"
"Somewhere in Sebastien, he has to still exist in some form. A spark of energy, a flicker of memory."
Stiles turned to the Beta. "Hang on... Liam, you said Mason said something right before he turned."
"He said, "That's not my name.""
Stiles turned to his friend. "He finally remembered his name."
Lena nodded. "Damnatio Memoriae."
Liam looked between the two. "That's what they wanted. They wanted Sebastien to remember his name."
Stiles turned to his friend and cousin. "Scott, Lena, you two know the myth of what happens when you call a werewolf by its given name?"
Lena frowned as Scott said, "It turns back to human."
Liam frowned, looking between the group. "What does that mean? Someone can just walk up to the Beast, yell Mason's name and turn him back?"
Scott shook his head. "Not someone... Lydia."
"Well where is she?" Lena wondered.
After finding out where Lydia was, Stiles drove them to the hospital and immediately ran to Lydia's room to see her neck bandaged.
Melissa walked into the room and Stiles asked, "What happened to her?"
"I don't know," Melissa replied as they walked towards the strawberry blonde. "Lydia, this is gonna have to be just between us, since I can get fired for it."
Scott smiled softly. "It's a cortisone shot. It's gonna bring the inflammation down."
Lydia nodded and lifted her sleeve to reveal her forearm.
Melissa shook her head. "Not there." She pulled the bandage from Lydia's neck slowly and positioned the needle.
Stiles made a move towards the door. "Oh, yeah, okay, we're gonna need to leave."
"You aren't going anywhere," Melissa said. "Stiles, hold her hand."
Stiles took Lydia's hand and braced himself. "Okay. Here we go."
Melissa moved the needle closer to Lydia's neck. "Okay. Here we go."
They heard a loud thud and noticed that Liam had fallen unconscious. Scott rushed to check on his beta. Lena also ran to Liam's side to check on him.
Melissa pressed down on the syringe. "Okay, Lydia, this is gonna hurt like a bitch."
They helped Lydia up and walked towards the elevator. Lydia winced with every step.
Stiles turned to Scott. "Okay. I'll get Malia. Text me when you find Parrish. Lena, don't do anything stupid. And Scott, she gets hurt, or worse, you're dead."
Scott nodded and said, "Hold on." He pulled out a package wrapped in brown paper.
"What's this?"
"Something I've been working on for awhile. Just make sure Malia gets it."
Stiles studied the package. "Is it Plan B?"
"It was Plan A."
Stiles frowned at him. "Plan A never works."
"This one will."
Stiles nodded and turned to Lena. "Be careful, okay?" He darted off.
Lena nodded. "You too."
They entered the tunnels and a sound caught Liam's attention. "Scott? You hear that?"
"I heard that," Lydia said softly.
Lena shook her head. "Save your voice."
"Hey... Lydia, get out of the water!" Liam yelled.
Lena pushed her out of the water and Lydia pulled her from the water just in time. Scott and Liam weren't so lucky and got electrocuted. They let out a pained scream. Theo appeared and threw Lydia down a grate and Scott caught her.
Scott fell, suddenly paralyzed.
"Feel that, Scott?" Theo asked. "Kanima venom."
Kasia glared at Theo. "What the fuck are you doing here?"
Lydia let out a scream of pain and against her urge to hurt Theo, Lena helped her Lydia up.
Lydia stopped in front of a door and they tried to open it. Lena tried kicking at the door, but it did nothing.
Kira appeared and used her sword to pierce the wood. The door opened. "Sorry I'm late."
"No, it's perfect timing," Lena told her with a smile.
Kira smiled and they ran into the room.
Lydia yelled in a weak voice, "Mason!"
Kira glanced at her. "I think you're gonna need to try a little louder."
Lydia nodded and yelled louder, "Mason!"
The Beast was encased in black smoke and the smoke filled the room before dissipating. Corey materialized from the wall and hugged Mason.
The Beast appeared in the black smoke and tried to escape. Parrish, who was flaming, held him back with a struggle. "Scott!"
Scott picked up the cane/sword and threw it into the middle of the smoky Beast. "No!"
The smoky Beast dissipated and Scott looked around. "Is everyone okay?"
"Not everyone," Theo replied, lightning surrounding him. He shot a bolt at Scott.
Kira blocked the bolts with her sword before saying, "The Skinwalkers have a message for you, Theo. Your sister wants to see you."
Kira raised her sword and stabbed the ground. A crack formed and made its way towards Theo. A hole opened up and a girl rose halfway from the hole. She grabbed Theo's ankles and pulled him down.
"Scott, help me!" Theo cried. "No! No! Scott! Help me, Scott. No! Scott! Help me!"
Lena covered her eyes, not wanting to see more than she'd seen.
---
Later, Kasia made her way to the station and listened to her uncle. "You saved their lives. Mason. Malia. Half the population of Beacon Hills. That's got to feel pretty good."
Stiles nodded. "It did. For awhile."
"But it's something you want to feel again."
"Yeah. Yeah, I think so."
Sheriff Stilinski smiled. "Welcome to your future career in law enforcement."
Lena grinned. "Law enforcement, huh? Nice."
---
They made their way to the library and met up with Lydia and Scott.
Lena let out a sigh. "I was hoping Kira didn't have to leave. I liked her."
Lydia turned to her. "But she'll be back. She still has to graduate."
Stiles glanced at his cousin. "That's the thing, though, I don't know... When we started this school year, I was so stressed about everyone ending up in the same place after we graduate. But I don't think it matters. We always seem to find each other anyway." He turned to Scott. "Even Allison. He didn't tell you. It was in the tunnels... When Sebastien had his hands around Scott's throat. The guy probably didn't even know what he was doing. His claws got into Scott's neck. He was going to kill him, but then he stopped and he said a name... Marie-Jeanne."
"He saw Scott's memories."
"He saw Allison."
"They must have looked like each other."
Lena shook her head. "No, they must have looked exactly alike. Doppelgangers. So weird. But really cool. Hopefully not like Supernatural's Skin."
Stiles nodded and continued. "It gave Scott a chance to break free. She saved him. Allison saved him."
Lena smiled. "She saved us all."
The young Chimera walked off and found a book containing information about the Ghost Riders. As she read it, she realized that things were about to get a lot more troublesome.