Parrish pursues the Beast. Gerard and Chris follow behind in an SUV. Gerard has the Surgeon's cane/sword. He says it is the pike Marie-Jeanne used to kill the beast in the 18th century. Chris questions if the cane/sword will kill the Beast. Gerard says, "You're damn right it will."

~~~

Stiles has just brought Mason's medical chart, obtained from Melissa, to Deaton in hopes that he can share some insight.

"Vanishing twin syndrome...?" Deaton asks.

"This is part of your expertise, right?" Stiles asks.

"Not particularly, no" Stiles frowns in disappointment as Deaton studies the chart. Just then, a loud noise is heard as Liam, Selene and Scott appear in the doorway, holding up The Surgeon, who is gravely injured.

"He's still alive!" Selene says.

~~~

Theo is badly injured after his last run-in with the Beast. Tracey helps him back to his lair. Theo seduces and kisses her. She apologizes because she's "not like the others" and therefore can't take his pain away. He stabs his claws into her to take her power. She struggles but he manages to absorb her power and kill her. Deucalion says, "And then there were none."

~~~

A near-naked dead body lies in the road. Sebastien is in a car. The device is unfamiliar to him until he manages to access Mason's memories and "remembers" how to drive.

~~~

Braeden is outside the front door of the McCall House, peeking around the doorway inside where the Desert Wolf is lurking downstairs. Up in the hallway, Malia is dialling a number into her phone when her mother shouts up to her.

"Who are you calling, Malia?" The Desert Wolf asks. Malia immediately stops typing and shares a concerned look with Cheryl and Reed. "Is it Stiles, your boyfriend? Tell him to come. Bring all your friends, if you want" Malia hesitates, clearly torn between her desire to call for backup and her unwillingness to put her friends in more danger. "Go ahead, Malia. You tell me how many people I'm going to have to kill tonight" Malia shares another look with the two other teenagers before turning off her phone.

~~~

The Surgeon is laying on the exam table while Stiles, Deaton, Scott, Selene and Liam surround him, looking concerned.

"Can you keep him alive?" Scott asks.

"I'm not sure he technically is alive" Deaton replies.

"Screw keeping him alive! How do we get him to talk?" Liam asks.

"Personally, I don't think we utilize torture nearly enough..." Stiles adds and Selene chuckles at the two. Deaton gives Stiles a look, just as a loud whispering is heard.

"Come..." Liam frowns and looks at the others.

"Did you hear that?" Liam asks.

"I heard that" Selene says and her eyes glow red as she starts to walk towards the exit.

Suddenly, The Surgeon bolts upright and causes an ear-splittingly loud noise to ring loudly throughout the room, which forces Deaton, Scott, Liam, Selene and Stiles to cover their ears with their hands. While they're distracted, The Surgeon stands and gets ready to leave. He pushes Selene out of the way. Liam growls and lunges toward him before Scott can stop him.

"Liam, wait!" Scott yells.

The Surgeon turns and causes an electromagnetic concussive blast that shoves Liam backwards into the wall behind him before he crashes to the floor. The Surgeon walks out the door and raises his hand before he walks into the parking lot, which causes all of the metal furniture to fly toward the door to the exam room. Liam gets to his feet, rubbing his sore neck, but when he and Scott start to chase after The Surgeon, Selene stops them.

"Stop. It's electrified" She explains and Stiles helps her up. Scott's eyes widen in shock, and he gently holds out his hand to feel the static electricity coming off of the furniture.

Meanwhile, The Surgeon has just made it outside, and after using his powers to knock out all of the lights, he falls to his knees. Sebastien approaches him and gives him a hard look before he takes The Surgeon's mask off, revealing a withered old man underneath with sparse white hair and blood pouring out of his mouth. It's Marcel, the friend who covered for Sebastien in the 18th century, and his friend looks horrified by his appearance.

"Marcel... if this is what immortality looks like, I think you might have been misled" Sebastien states.

"For you... All for you..." The Surgeon replies.

"What did you do with it, Marcel? Where's the pike?"

"The Argents..."

Inside, Scott's eyes widen in shock when he realizes what they're talking about.

"The Argents... The cane!" Scott realises.

"But they took it. They took the cane" Liam responds.

~~~

Parrish has lost Sebastien's trail. Realizing that he must know they have the pike, Gerard suggests they stop chasing him and make him come to them.

~~~

Braeden has her rifle aimed inside the house while she takes cover next to the front doorway. She trains her laser sights as close to the Desert Wolf as she can and takes a shot, which just barely misses her when she ducks into the dining room. The Desert Wolf smirks in amusement.

"Almost, Braeden... But not quite. You'll get another chance. But you better make sure it's a headshot" The Desert Wolf taunts.

Malia, still upstairs, walks toward the staircase, and when the floorboards creak, the Desert Wolf smiles and walks toward the staircase as well. Reed quickly grips Malia's wrist to stop her from going further.

"Coming down, Malia?" The Desert Wolf asks.

Outside, Braeden looks scared.

"Malia, don't move!" She yells.

Malia does as she's told and freezes upstairs in the hallway. She looks at Cheryl and Reed with a worried expression, which they return.

~~~

Deaton, Scott, Stiles, and Liam are gathered around the table in the exam room, where Scott is flipping through the pages of Mason's chart.

"Maybe there's something in here? Something about how he was a genetic chimera. Mason had a vanishing twin..." Scott realises.

"Now we've got a vanishing Mason." Stiles replies.

"What does that have to do with him turning into a 250-year-old French guy? How does that even happen?" Liam asks.

"Hold on... Scott might have something. Mason's twin wasn't entirely gone-" Deaton starts.

"That's what made him a genetic chimera. The DNA was still there. Metaphorically speaking, the DNA of Mason could still be inside Sebastien as well" Selene realises.

"How?" Stiles asks.

"Life is energy." Deaton explains and Selene nods.

"Energy doesn't just disappear. 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" She adds. Liam's expression becomes hopeful at this news.

"So, Mason just can't be gone?" he questions.

"Somewhere in Sebastien, he has to still exist in some form. A spark of energy, a flicker of memory..." Selene explains.

"Hang on... Liam, you said Mason said something right before he turned" Stiles remembers.

"He said 'That's not my name.'" Liam tells them.

"He finally remembered his name" Scott says shocked

"Damnatio memoriae." Stiles adds.

"That's what they wanted. They wanted Sebastien to remember his name" Scott reminds them.

"Scott, you know the myth of what happens when you call a werewolf by its given name?" Selene says with a smile.

"It turns back to human..." Scott realises what Selene is onto.

"What does that mean? Someone can just walk up to the Beast, yell Mason's name, and turn him back?" Liam asks confused.

"Not someone..." Selene says.

"Lydia" Stiles realises.

~~~

Sebastien has just walked up to the front desk at the station, where Valerie Clarke is working.

"Who did you say you were looking for?" she asks him.

"The man's name is Argent" Sebastien replies with his french accent. Just then, Sheriff appears in the doorway of his office.

"Did you say 'Argent?'" Stilinski asks.

~~~

Later, inside the Sheriff's office, where Sebastien is sitting in a chair in front of the desk. Sheriff's phone buzzes, and he glances at the screen to read his texts.

"Sorry, my son likes to leave-" His phone buzzes again, and Sheriff looks momentarily concerned at whatever the message from Stiles says, suggesting that Stiles warned him about Sebastien. However, Sheriff quickly puts on his poker face to hide this revelation. "-Incredibly long and incredibly confusing messages" Sebastien looks at him curiously, and Sheriff gulps nervously before sitting behind his desk. "Maybe I should just turn the damn thing..." the sheriff shuts off his phone and sets it down on the desk before finally addressing him. "So... You're looking for one of the Argents?" Sebastien concentrates on the sound of Sheriff's heartbeat, which is quick enough that he can tell Sheriff is anxious. He smiles in satisfaction.

"You seem to know who I am. That means you know what I'm capable of" Sebastien reminds him. Sheriff takes his sidearm out of the holster on his hip and sets it down on the desk with a glare.

"I've got some experience"

"Your weapons may be more sophisticated than the arrows and the bullets of my time, but they still won't kill me" Sabastien seems amused and the sheriff scoffs.

"I'm pretty sure a 9mm Beretta will do more damage than an 18th century musket"

"Are you certain? I can walk out of this place with my hands clean... or, I can walk out with them drenched in blood. Your choice. Now, if you won't help me with the Argents, I'm also searching for an old friend. Could you tell me where I can find Elijah Vulpes?" The sheriff seems taken aback with this news.

"I'm afraid the person you're looking for is dead. Now, leave" Sebastien listened to his heart and realises he tells the truth.

"How?"

"Most people don't survive more than 250 years" Sebastien doesn't look pleased with this information and the sheriff gulps.

"You know something" he notices. The two men stare at each other. Sebastien closes his eyes and searches Mason's memories. "Selene" he eventually says and stands up from his chair.

~~~

Clarke watches as Sheriff leads Sebastien out.

"Sir?" Clarke asks confused. When she sees the gun in Sheriff's hands, she immediately goes into defense mode, pulling out her own gun and aiming it at Sebastien. Sheriff looks horrified and immediately tries to stop her.

"Clarke, don't!"

"Stop where you are" Clarke orders.

"Let him go" the Sheriff says while starting to panick. Sebastien's fangs and claws come out, and his eyes begin to glow bright blue as he turns to lunge toward Clarke. Sheriff aims his gun at Sebastien and shouts at him. "No!"

Clarke and Sheriff both start shooting at Sebastien as he rushes toward Clarke. Though the bullets do slow him down somewhat, they don't stop him, and he presumably knocks both of them out.

A moment later, Hayden walks into the station with Liz to see her sister and is horrified by the sight of an injured Sheriff crawling toward where he dropped his gun several feet away. Lydia has just come into the bullpen and is staring wide-eyed at Sebastien as he stalks toward her.

"Lydia!" Liz yells as she runs towards her friend.

Sabastien wraps his clawed hand around Lydia's throat and rears back his other arm to claw out her chest when Lydia suddenly Banshee-wails in his face, thrusting her hands forward and using the force of her voice to throw him backward toward the Sheriff's office.

Hayden looks shocked at seeing Lydia's powers in action and concerned as Lydia wraps her hands around her seriously bleeding throat and Liz catches her before she can fall to the ground. Sebastien slowly gets to his feet and looks over at Hayden, who is beginning to panic. When he closes his eyes, he sees Mason's memories of Hayden and ascertains her identity.

"Hayden. Your name is Hayden" He states. Hayden's eyes widen in fear as Sebastien lunges toward her.

~~~

Liz is supporting Lydia as she rushes through the front doors to the emergency room. Lydia is still applying pressure to her bleeding neck wounds and is becoming weaker by the moment.

"Melissa! MELISSA!" Liz yells.

~~~

Braeden is still ducked down on the back porch and trying to use her laser sights to get a shot at the Desert Wolf, who is still hiding behind the wall next to the staircase with her gun raised while Malia hesitates at the top of the steps.

"Malia... Come down" Corinne says.

"Don't listen to her!" Braeden yells.

"I'm not going to stop, Malia. I'm taking back what you stole from me"

Malia looks furious as she mutters under her breath.

"I didn't steal anything" Malia says.

"But you did" The Desertwolf starts. The Desert Wolf starts to walk closer to the staircase with her gun raised. "And I don't care if you're a willing participant or not. Talia Hale spent nine months trying to convince me of the miracle of childbirth. You know what it really felt like? A parasite. Talia said it was a gift, that the coyote passes down part of her power to her daughter. She called it 'beautiful.' I call it theft."

Malia looks at Reed, who nods and she slowly makes her way down the steps. When the Desert Wolf hears the creaking stairs under her feet, she comes out into the open to shoot at her. Reed quickly interfeers and helps Malia duck out of the way just as Braeden takes a shot at the Desert Wolf from the porch. One of the shots hits her, but not in a critical area, and others shatter some of the windows. Meanwhile, when the Desert Wolf shoots at Braeden, she gets hit in the side with a bullet and turns to take cover as she applies pressure to her wound and groans.

~~~

Sebastien has just brought a slightly injured Hayden into the DREAD DOCTORS' OPERATING THEATER. Hayden notices Tracy's dead body laying on the ground next to the large syringe filled with her Kanima venom, but Sebastien is too preoccupied with finding the pike.

"Where is it?" he yells as he throws over a table.

"I brought you here like you wanted. How about letting me go now?" Hayden asks, clearly afraid. Hayden kneels next to Tracy's body and gently closes her eyelids as Sebastien stops and stares at the fresco on the wall. Hayden looks over at the syringe next to her and picks it up before slowly walking so she's standing next to him but somewhat in his blind spot. He studies the painting for another moment before pointing at it.

"This demon on the left-- what is he?"

"He's called a Hellhound" Sebastien closes his eyes to look through Mason's memories for a moment.

"Parrish... His name is Parrish, isn't it?" Hayden looks nervous as she continues to keep the syringe out of his sight. "And the Argents will try to put the pike in his hands" He looks over at Hayden, who sees her opportunity to take out the syringe and try to inject him in the neck with it. However, Sebastien easily sees this coming and grabs her by the arm, twisting it backward so hard that her arm breaks and she drops the syringe onto the ground. "When did young people become so confident?" Sebastien shoves Hayden backward until her back is flat against the wall before plunging his clawed hand into her stomach, causing her to moan in agony. He hears one of the Argent sound emitters and leaves her behind.

~~~

Elsewhere in the UNDERGROUND TUNNELS/SEWERS, Theo and Deucalion are walking through a hallway when they suddenly stop at the sound of a high-pitched screeching noise.

"I know that sound" Deucalion realises.

"It's the Argents, isn't it?" Theo asks and Deucalion nods.

"Drawing the Beast to them. Corralling it. You'll need to be back at full capacity"

"Let's find out" Theo breaks a pipe off of the wall, exposing the electrical wires running through it, before he grabs onto it in the same manner that Josh used to. He then extends his free hand toward Deucalion, which releases a bolt of electricity that shocks him so much that he falls onto the ground. Theo smiles smugly before he walks toward Deucalion as he struggles to recover. "Looks like it worked!"

"You know, Theo, someday, your willingness to stab anyone and everyone in the back might turn out to be your downfall"

"Don't worry! You can still have Scott and Selene's eyes. I'll just be bringing them to you" Theo walks away, leaving Deucalion on the ground to recover from the electricity.

~~~

Stiles is in Lydia's room, where she is sleeping soundly in her bed, her neck bandaged up where Sebastien clawed her. Liz watches as Stiles takes Lydia's hand in his own and squeezes it affectionately, which causes her to stir awake. Stiles sighs in relief.

"Hey, you all right?" Stiles asks. When Lydia speaks, her voice is a weak rasp due to her vocal cords being affected by her injury.

"Did... Did you find something? A solution?" She asks. Stiles takes a deep breath and looks at her with a saddened expression.

"Yeah... It was you. It was you, Lydia" Lydia looks devastated by this news.

~~~

Parrish is in the tunnels, having just read a text message on his phone, when Chris, who had been searching the tunnels, catches up with him. Parrish looks at him with concern.

"Lydia's been hurt. Badly" Parrish informs him, clearly concerned about her. The Beast's growls are heard, indicating that he's rapidly approaching them. Chris is clearly concerned by this news, but forces him to stay on task.

"It doesn't change anything" Chris tries to get Parrish to focus.

"What if she's dying?"

"If we don't stop Sebastien, she will die. He's not just coming for the pike-- he's coming for anything that stands in his way. Right now, that's all of us" The growling and stomping noises get louder as the Beast closes in on them, and Chris puts his gun down as Parrish looks at him in confusion.

"What are you doing?"

"You saved my life once. Now, I'm going to save yours" Parrish makes a concerned and confused face.

"I'm not sure I'm getting the strategy here"

"You're the strategy, Parrish. You're the one in the fresco-- put there as a reminder that the Beast isn't unstoppable. Whoever painted it, they didn't see a guy with a gun facing down the Beast. They saw you. They saw the Hellhound" Parrish looks torn, but is seemingly motivated by Chris' pep talk, because his eyes begin to glow reddish-orange as he bursts into flames, preparing to fight the Beast when he finds them.

~~~

A saddened Liam is sitting out in the hallway when Scott walks out of Lydia's room to join him.

"Is she okay?" Liam asks.

"She's gonna be fine, but... she can't really talk" Scott explains. Liam's expression goes from sad to defeated, and his shoulders slump as he sighs.

"Then its over, isn't it? There's nothing we can do to save him" Scott looks heartbroken, both for Liam and for his own feelings over losing Mason. Just then, his phone buzzes, and he sees that he has two missed voicemails.

"Give me a second" Scott walks a short distance down the hall to listen to the voicemails that Kira left him.