Just a little headcanon I came up with for Jus in Bello.
Please note: I am still catching up on Supernatural. I am currently watching the start of Season 4. For all I know, Nancy is going to return in two episodes and ruin this theory. It doesn't seem likely, but if this is the case, please don't spoiler in the comments.
Nancy Fitzgerald: "Hey, that's Jenna Rubner."
Sam Winchester: "That's not Jenna anymore."
- Jus in Bello, Supernatural, Season 3 Episode 12
One snowy Saturday when she was eight, Nancy Fitzgerald locked herself in her bedroom for two hours. She took with her glitter and safety scissors and pink card, and when she was done with it all she tidied her crafts away and put the finished object in her backpack.
The next day, she took it to church.
She was always the first to arrive for Sunday School, but this time she couldn't sit still. She got the card out, and held it in her hands, checking over and over again that everything was perfect.
Mrs Henford walked over with a smile. "What have you got there, Nancy?"
"Valentine's card." Nancy blushed.
"Really?" Mrs Henford knelt next to her. "So which boy has been lucky enough to earn such a pretty card?"
"It's for Jenna."
Mrs Henford stopped smiling. "Nancy. I need you to look at me."
Nancy forced her eyes off the ground. Mrs Henford looked very serious.
"Nancy, there are some things which you can do with boys that you can't do with the other girls. Little girls can give Valentines cards to little boys, but you can't give one to Jenna."
"But she's my friend!"
"Yes, but she's a girl." Mrs Henford put her hands on the card. "You have to be careful, Nancy. The Devil is always looking for your weakness. Is there a boy you'd like to give this to instead?"
Nancy shook her head.
"Well then, I guess you don't need it after all."
Nancy watched in silence as Mrs Henford took the card away, walked over to the wastebasket, and dropped it inside.
In the winter of their sophomore year, Nancy stayed over at Jenna's for a sleepover. This wasn't all that unusual – they had been best friends for as long as anyone could remember – but this sleepover Nancy would always remember.
"But enough about Jack! What boys do you like?"
Nancy laughed, but Jenna kept looking at her.
"Well, I don't know..."
"Oh, come on Nance! You know all about who I'm crushing on, but you never talk about who you like. Don't be shy!"
Nancy shrugged. "I don't think there is anyone I like at the moment."
"Fair's fair, you have to tell me something! I don't think I even know when you had your first kiss."
Suddenly, Nancy was very interested in the ceiling.
Jenna stopped laughing. "Nance? Tell me you've had your first kiss."
She couldn't meet Jenna's eyes, but she shook her head.
"But you're sixteen! I thought you were just shy about it... Not even a Spin The Bottle kiss?"
"I never really played..."
Jenna had leant over, and before Nancy could move they were kissing.
"There!" Jenna said. "Nothing to be scared of! Now you know what to expect."
"But... we're girls, we aren't meant to..."
It was a sin to want to kiss other girls. So why did she wish she could do it again?
"Oh, relax!" Jenna laughed. "It was only one time. Now, what boys do you want to practise with?"
She joined the police department as a secretary in August when she was twenty three. In September, Phil asked her out on a date. The entire night was awkward, but it wasn't until he kissed her goodnight that Nancy allowed herself to think it: I wish Jenna were here. When he asked again, she turned him down. He didn't ask why.
That January, on her birthday, she and Jenna went to the cinema and giggled their way through Enchanted. When Jenna drove her home, they sat outside in the car talking until nearly midnight. As Jenna drove away, Nancy wished she didn't have to work the next day.
When the Winchesters walked into the station, Nancy was struck by how normal they looked. She had been expecting monsters, but they just looked... human.
She remembered everything she had learned from Mrs Henford about the Devil walking among the people unseen, and she knew it had all been true. The Devil was walking right past her, smiling, and she held her rosary and prayed that they couldn't see every evil thought she had ever had written onto her face.
She knew it was ridiculous – they were just two men, they couldn't possibly read her mind – but that didn't stop her from jumping when the shorter one knew her name, even though she knew it was right there on her desk.
When they were out of sight, she breathed deep and tried to calm down. But she couldn't shake the feeling they had recognised her for what she was.
A sinner like them.
When Sam grabbed her through the bars of the cell, Nancy was sure he was going to drag her down to hell. She had known she shouldn't do as he asked, but his brother was wounded and she wasn't about to let someone bleed out right there in the cells, no matter how evil they might be. But then Sam had pulled her up against the bars, and for a second she had been certain he would say it: "I know what you are."
But then Phil was there, pulling her away, and she got out of there as quickly as she could. In the corridor outside, Phil asked if she was alright.
"I'm fine." She walked away from him as quickly as possible, and wished she were safe at Jenna's house.
When the demon came out of Henriksen, Nancy realised she had been right about a lot of things.
But she had also been very wrong.
Demons were real, but they were black smoke which took you over and you couldn't not know it was in you. The Devil could attack anyone, and right now he was after everyone in here, but for the moment, the Winchesters were free of him, and so was she.
The first time she walked over the Devil's Trap, Nancy held her breath, but she felt silly afterwards. She wasn't a monster.
She was just human.
When the demon offered to cut her heart out, Nancy was scared.
It would hurt worse than anything she could imagine, she knew that. It would hurt and hurt and it would kill her, and then she'd probably go to Hell for witchcraft and be tortured for eternity. All there would be for her was death, and pain.
But she wanted to do it anyway.
She remembered Jenna, her eyes black and dead and cold, so different from her usual smile. She wanted Jenna to laugh again, and this – this could save her.
"I'll do it."
When she was on the roof, Nancy felt strangely calm.
She had wanted to die to save Jenna and the others, but Dean hadn't let her. Dean, who fought evil every day, thought she was worth saving. Thought her life was worth living, even when the Devil was at the gate and their backs were against the wall.
She was a good person. Forget the rest – today, she was fighting demons, and if that wasn't good, she didn't know what was.
If she lived through this, she could do anything. Perhaps, she could even tell Jenna the truth. If she did, it had to go right for her, because if she lived to see tomorrow she wasn't just good, she was invincible.
She made a promise to herself.
"When this is over, I'm going to have so much sex."
Phil looked surprised.
"But not with you."
No, it wasn't Phil she loved.
When it was all over, Nancy stayed behind. Jenna had been injured – a salt wound in her leg, nothing fatal. She had wanted to go to the hospital with her, but half the town was there tonight, and she owed the Winchesters a false statement at the very least. Once that was done with, Nancy realised that someone had to help clean up, and she volunteered.
After all, she had the rest of her life to spend by Jenna's side.
"Excuse me." Nancy didn't recognise the little girl. "I'm looking for two boys. They're brothers. One's really tall and one's really cute."
She would just deal with this, and be on her way.