Castiel dialled Dean's number and sighed when he received voicemail.

"Damn it, Dean" he muttered shoving his hands into his jacket and heading towards the university. He had his suspicions about Lily, he couldn't put his finger on why but her distance and lack of not answering calls made him suspicious and curious.

Castiel stared up at the now closed university and headed towards the door Lily had told him to go through. A nervous feeling swept through him and he opened the door poking his head around the dark corridor and swallowing hard.

"Lily?" he called stepping in and jumping when the door clicked loudly behind him. In the distance of the building he could hear the whir of a hoover going off and sighed looking around.

"Lily?" he shouted. "I'm here, you called me"

Slowly the lights in the corridor flicked on and he looked up at the ceiling alarmed.

"Hello, Castiel" Lily said stepping forward both of her hands in her coat pockets. "I'm glad you came"

"Why am I here? Why are you here? It's after hours…no one is here expect the cleaners, Lily"

"Because it's the only place I could think to do this, to do what must be done" she said in a cool determined voice"

"An experiment?"

Lily laughed and shook her head. "Has Dean contacted you?"

"No, well not recently but I keep calling him and he won't answer" he said with a shrug. "Why?"

"Do you want to know why he isn't answering you?" she said stepping closer to him, her heels tapping and echoing in the halls loudly.

Castiel eyed her suddenly feeling rather scared and nodded.

"Because he's currently lying in his garage unconscious, I pray that the wrench I knocked around his head hasn't done any damage to his beautiful head" she said folding her arms. "There was a bit of blood"

The breath inside Castiel escaped in a harsh puff and he stared at her in complete horror.

"What?"

"You're exactly the same aren't you? Always questioning, always wondering, haven't you figured it out?" she shouted making him step back from her. "I mean it was a little difficult but you still haven't figured it out have you? It's just remarkable what an act can cover up, I smile and you take it because you don't see me, you see the happy, smiling, Lily Grace"

"It's you" he whispered stepping back from her. "You're…stalking us?"

"Ding, ding, ding, 100 points for the cute doctor over there" she said raising her hands up.

"You shouldn't have introduced me to him all those weeks ago"

"Since then?"

"Oh yes"

Castiel gaped at her when she simply stared at him. "You spiked me"

"You should be dead, the pills I slipped into that beer were enough to kill a man and lucky you survived it all"

Sick flooded in Castiel's throat and he gasped moving away and hitting a wall. "You're sick!"

"That's one word for me"

"You tried to kill me?"

"Yes"

"Why?"

Lily looked him over and nodded looking down at the ground. "Because of Dean, I want him because he reminds me of Mark, Castiel, that sweetness, that tenderness, and the love he holds in his heart for you is what I want! Why should you have him? You're a little whore, Castiel; kissing other men like that…I reckon you've spread your legs for many more"

"You text Dean"

"I also was behind the silent phone calls, the messages, and I also have those delightful photos!" she said with a small smile. "I scribbled out your face and cut them out; if you like I can give you a bag full of your heads"

"What is wrong with you?" he whispered in horror.

Lily bit her lip and shrugged looking away with breathless laughter. "Everything and more"

"This is insane! You can't…Dean is my partner, not yours, and he certainly can't be Mark"

"I don't want him to be Mark!"

"Then what do you want!"

"I want you dead" she whispered in a cold voice, her eyes maliciously dark. "That's what she wants"

"Who?" he whispered looking down the corridor confused.

"The voice" she said tapping her head.

Castiel throat convulsed and he stared at her with wide eyes. "You hear voices?"

"Voice, it's the voice of my biological mother"

"Isn't she dead?"

"Yes, but that doesn't matter"

Castiel inhaled closing his eyes and opened them looking away.

"You're not well, Lily, hearing voices is not normal. You are not hearing your dead mother and Dean can never be the Mark you want, Mark is dead and he's never coming back"

"Don't you think I know that? Dean can be his replacement" she said moving towards him and poking him hard in the chest. "You know nothing about me"

"You never told me"

"You never asked!"

"Well tell me then" he hissed.

"I met Mark when I was only fifteen, I was adopted into a loveless family, a mother and a father who couldn't care less about me…he was my saviour in every single way. I fell so in love with him that it hurt when we argued or we fought, he is the love of my life. The night he died was the night we had our biggest argument and I called him a waste of space, an idiot, and then he went out for me, to get us food, and I told him I meant every word… I didn't really; I just wanted to hurt him and I waited hours for his return" she said and looked up to Castiel with bleary eyes. "Do you have any idea what it's like to get a phone call from a stranger to tell me that his car hit a skip and impaled himself? Do you have any idea what it's like to learn the one you love is dead!"

"No"

"No, you don't and after tonight you never will"

"Why Dean?" he whispered moving off the wall and edging away from her.

"Because he's perfect for me, I'll cheat, I'll never lie, and I'll certainly never hurt him"

"By killing me?" We're together, Lily, I love him and he loves me…do you really think getting rid of me will get you Dean?"

"I don't know but I can try" she whispered and stopped removing a scalpel from her coat pocket. "I think cutting your own head off will be a start!"

"Lily, don't do this, don't listen to that voice in your head!" he shouted at her when she cocked her head like a woman possessed.

"It's been with me since Mark died"

"Because you're a sick woman, Lil, you need help" he said desperately. "This isn't the way! Murder, killing, and stalking people is not right, Lily, and you know that"

"I know nothing anymore" she whispered pointing it at him. "All I know is I have to get rid of the opponent"

"Killing me!" he said backing away from her. "Lily, please…"

"I'm sorry" she whispered softly. Castiel ducked when she swiped at him and turned on his heel pushing her against the wall.

"Stop this"

Lily gasped freeing her hand and managing to cut a sharp line across his hand. Castiel gasped in pain letting go of her and taking off down the corridor, he ran and heard her coming fast behind him as he darted up the stairs clutching his bloody hand and found the nearest cleaning cupboard. Castiel held the door fast with his bloody hand and scrambled for his phone dialling Dean's number.

"Come on" he hissed hearing it dial and exhaled shakily when he heard the door go and footsteps echo.

~0~

Dean's head throbbed and he could feel a vibration and a noise surrounding him. He opened his eyes to see the wheel of the car he was working on and a wetness covering his hair and neck.

"What" he whispered and sat up clutching his head. "Lily"

Dean looked down at his jeans and fished out of phone answering the call. "Cas?"

"Dean, oh thank god" Castiel cried closing his eyes in relief. "Are you okay?"

"Well I'm covered in my own blood and I'm lying on the floor of my garage but that is not our biggest problem"

"Lily, yes I know, she's here with me in the university…Dean, you have to get here now!" he said urgently holding the door back when Lily attempted to open it.

"This is useless, Castiel, open the door!" she shouted.

"Did you hear that?"

Dean grunted getting up and nodded. "Yeah, what's she trying to do"

"Dean, she's the stalker and she's trying to kill me"

"Where are you?" Dean said grabbing his jacket. "Cas, where are you?"

"University, the labs, call the police"

"I'll be right there"

Dean hung up and dialled 911 straight away. "Police to the UCSF now! My boyfriend is about ten seconds from being stabbed by a manic girl, the labs"

Dean hung up and sprinted towards the university without a second thought to his current state.

Castiel held onto the door fast. "Lily, don't do this!"

"I have to do this!" she shouted at the wood of the door. "You don't understand…"

"I understand that you're not well, you're not mentally stable, Lily, you stalked us! How is that healthy and normal?"

"I did it because I had to"

"Everyone has a choice" he said closing his eyes and gritting his teeth at the pain in his hand. "This is the wrong choice"

"Why can't I have my happy ending?" she whispered and gasped when a door opened and an out of breath Dean arrived.

"Lily" he said breathing hard when she pointed the scalpel at him.

"Oh" she said cocking his head at him. "He called you I see"

"Lily, what are you doing" he said noticing the blade was coated with blood.

"I'm doing what I have to"

"Killing Cas? Lily, you're not a killer"

"How would you know?"

"Because I've got to know you, those lessons when you opened up bit by bit…I saw you, Lily, and this here…this is insanity"

"It always wins" she whispered looking at the closed cupboard door and back to Dean. "She wants me to do this"

"Who?"

"The voice in my head is telling me to do this"

Dean blinked and nodded. "Okay, you hear voices…"

"Voice!" she hissed at him. "It's always there, Dean, I can't get rid of it! Pills don't work"

"You stalked us"

"It was the only way I could get to know you"

"By stalking us? You nearly killed Cas didn't you?"

"It didn't work" she said with a sigh. "Did you ever think it was me?"

"I had my suspicions"

Lily chuckled looking at the door where Castiel was pressed against the door listening to every word.

"Of course you did, you know he's cheating on you"

"He isn't"

"He's a dirty little whore, kissing boys, spreading his legs for anyone who breathes on him" she murmured with a smirk. "The love of your life…"

"You're a liar" Dean said shaking his head at her. "How could you possibly think I would be with you? You kill Cas and I just fall in love with you?"

Lily swallowed staring at him. "You could"

"No, I couldn't, Lily, because I love him"

"You can love again"

Dean shook his head and covered his eyes feeling a dull pain radiate down his neck.

"I can't love anyone else"

"Why not?"

"You spoke to me before about love, true love, that kind of love that is rare…I have that and he's currently bleeding and hiding in that cupboard. He could die and I'd still carry on loving him, Lily, just like you love Mark"

"He's gone"

"I can never be him, I can never love you like he loved you, I can't be him, Lily, and you know that. You're clinging on to his memory because that's all you have now and you're searching for that love in someone else…I'm taken" he said moving towards her slowly. "This voice inside your head is controlling you"

Lily bit her lip feeling tears shadow her eyes and she looked down at the lino. "I just want him back, I want to be loved again, and I need someone to be that person"

"That person is gone…Lily, hurting Cas is not going to make me love you or make anything better" he said closing in and holding out his hand. "So give me that"

Lily looked up at him with her cheeks covered in track lines from her tears. "I never wanted to hurt him; not really, he's my one and only friend"

"Please" he whispered looking at the scalpel and back to her. Lily slowly passed it to him and watched as he threw it on the floor out of reach.

"Stand over there" he instructed watching her back away and hit the wall with a sob.

"Cas?" he murmured knocking on the door.

Castiel swallowed opening the door to reveal Dean who looked him over. Castiel inhaled sharply seeing the blood coating Dean's shirt and threw his arms around him clinging to him.

"Are you hurt?" Dean murmured and drew back when Castiel shrugged showing his hand.

"It's nothing, how's your head?" he whispered looking at the blood.

"Sore but I'll live" he replied pressing his lips to his forehead.

Lily watched them and swallowed hard not knowing what to do or say. Sirens erupted outside and she gasped staring at the doors and back to Dean.

"You called the police!" she said in horror backing away from them.

"I had to, Lily, this is a serious offense" Dean said drawing his arms away from Castiel.

"You need help, Lily" Castiel injected looking at her. "They can give you that"

"No, no, no, they'll lock me up! They'll send me to a mental asylum and torture me!" she cried hysterically snatching the scalpel on the floor up. "No!"

Lily took off as the doors opened and the police came in.

"Lily no!" Castiel shouted running after her closely followed by Dean and the police. Lily ran down the hall and down the stairs back towards the labs. Lily ran towards the only open lab and pointed the scalpel at the cleaning lady.

"Run if you want to live" she said breathing hard. The cleaner dropped the mop and nodded frantically, Lily stepped aside letting the woman past. Lily slammed the door shut and looked around desperately, she darted forward turning on the gas valve and switching on all the taps around the room. Lily choked when gas started to flood in the room and looked at the door waiting.

Dean watched as the screaming cleaner lady ran past them. Dean, Castiel, and two policemen ran to the door and opened it up.

"Holy…" the policeman said stepping back with a cough. Castiel stood at the door covering his mouth and coughed.

"Lily, what are you doing?" he called being held back by Dean who eyed the room warily.

"An epiphany" she said with a choke. "I'm going to go see him"

"Who? Mark?" Dean said confused.

"Ding, ding, ding" she whispered staring at them all. "If I go with them, they will lock me up forever. I'll never be a nurse; I'll never have a job, a life, a relationship ever again!"

"That's not true" Castiel pleaded "You're just not well, the grief has made you ill"

"I can see him again"

"This is ridiculous" the policeman murmured.

"What's your name?" Dean said looking over to him.

"Victor Henriksen"

"Well, Victor, do you have a solution?" he hissed at him.

"Dean, don't" Castiel whispered looking to Lily who was crying.

"I can see him again" she said going into her pocket and pulling out a box of matches. "One light…and boom"

"No!" Castiel cried shaking his head. "Lily, you can't!"

"I'm sorry, Castiel, I'm so sorry for what I did to you…for what I did to Dean" she said brushing her tears away. "I was out of control, I just…I want him back and I saw him in Dean"

"It's okay, Lily, okay, I forgive you…just please come out" Castiel pleaded and went to move towards her when she held up the matches.

"One more move and I blow us all up"

"Find a way to turn off the gas from outside" Victor murmured to the other policeman who nodded taking off speaking into his jacket. "We need to get out now"

"Not without her!" Castiel said struggling against Dean's hold.

"Don't be stupid, Cas" Dean hissed dragging him back. "This is serious"

"She's going to blow herself up!" Castiel shouted at them both. "Lily, please"

"Dean, you know I'll do it" Lily said with a small smile before coughing erratically. Dean watched her and looked at Castiel.

"Victor, you got kids, a wife?"

"Yes, a wife and a daughter" he said confused.

"Well get out now, take him with you" Dean said dragging Castiel who yelped and gasped when Dean shoved him towards Victor.

"Dean, no!" he protested "Dean, she'll kill you both"

"Get out, both of you, I'll get her out" he said looking to Victor who studied him for a moment and nodded.

"Dean!" Castiel shouted when Victor gripped his arm tight hauling him away. "Dean, please!"

"I'll be right behind you!" he assured and watched as Victor took away a struggling and protesting Castiel.

"Bold move, Dean" Lily said quietly with a cough leaning on the desk. "What are you going to do? Pull me out of here?"

"If I have to…Lily, this is madness"

"That's my middle name if I had one"

"Lily, you have no idea what happens in the afterlife" Dean said feeling a little desperate. "You might never see him again"

"I won't know until I try" she whispered with a small sniff and opened up the packet of matches. "You better get out of here, Dean; you don't want Castiel turning into me because he loses the one he loves"

"Lily, don't do this"

"You can't stop me" she murmured taking out the small match and staring at it. "This is the only way now…it's my fault he died, Dean"

"No…"

"Yes, yes, it is and I can never, ever, forgive myself for what I did to him and now to you two" she said with a small laugh. "How am I supposed to live on with this guilt, this loneliness, and this despair?"

"That's life and we take it every day at a time, Lily, because we have to. People die every day"

"Yes, they do don't they" she murmured looking up to him through the gassy haze. "Like I said, Dean, you better run for your life"

Dean stepped back watching her hold up the box and the lighter.

"One last thing, tell him I'm so sorry and yourself…my mind wasn't my own"

"Don't do this" he pleaded one last time in desperation.

"Run" Lily hissed at him. Dean moved away from the door staring at her tearful eyes with no emotion. They were blank just like her expression and she nodded watching him give in and take off running down the corridor.

Outside, Castiel fought with the policemen who restrained him down as a fire engine came screaming into the scene.

"They both could die, you have to go back in there!" he shouted angrily.

"We can't, sir, it's too dangerous"

Castiel huffed out in annoyance turning towards the university and looking at the people surrounding the area talking in hushed tones. He bit his lip willing Dean to come out and moved back towards the building when the door suddenly opened revealing the man himself.

"Dean!" Castiel shouted running towards him and jumping at him. Dean clung to him hard when Castiel sobbed into his neck.

"I had visions of you running back inside" Dean murmured in relief when Castiel trembled and pulled back.

"Lily?"

Dean shook his head looking over to Victor who nodded once turning towards his team.

"She was adamant, Cas, I couldn't without…" he trailed off when Castiel looked at the building. Dean looked too and they could only wait for the inevitable.

~0~

Lily choked falling onto the ground unable to breathe anymore, her vision swirled and her hearing dimmed. Tears fell down her cheeks and eyes as she stared at the match; she looked up slowly and gasped sharply. Lily didn't know if it was her own twisted mind, the gas, or real as she stared at Mark.

Loose dark curls fell on his forehead as he looked at her cross-legged on the floor.

"You're here" she whispered in surprise. Mark didn't answer as he reached forward brushing a curl away from her forehead and watched her in concern.

"I have to do this" she murmured holding them up. "Don't I?"

Mark moved his hand and cupped her wrist softly with a small nod. Lily gasped at the cold touch and looked down at her wrist and back up to nothing; she looked around desperately and knew it was a sign. Lily straightened up tossing back her curls and held the match against the box with trembling hands. With a soft exhale and a strike that sparked the light, Lily's world erupted into fire, pain, and then…silence.

A/N: She was always going to die before I get protests.

Enjoy, folks, and do not fret! Everything will be resolved, Balthazar, Pamela/Jo, and so on.