Disclaimer: i do not own Glee or its characters. I only own Olivia.

My Best Friend's Girlfriend is a Mystery

Puck knew only three things about Finn's new girlfriend; which wasn't much.

He knew she was different from Rachel and Quinn. The girl walked around the halls of McKinley without a care in the world. She would sway those pretty little hips and Puck couldn't lie, he was envious. Not jealous of Finn, the dude deserved to be happy after the bullshit he, Quinn and Rachel had put him through during sophomore and junior year. He still didn't know the full details of why Berry and him broke up but the mooneyes she was giving him didn't go unnoticed by Olivia.

That was her name. Olivia, she never really gave out her last name. Finn called her Livvy with the a goofy smile but other than that, he almost always called her by her Olivia. He also noticed that she wasn't too big on public affection, no making out in the hallway. Finn carried her books, following behind her like a devoted puppy. Occasionally she let him hold her hand. Most of the time, she kept her hand on his thigh, or she would run her nails along the nape of his neck and Finn would shiver. Artie once commented that it was a bit kinky. It only brought a smile to both Olivia and Kurt's faces.

That was another thing he knew about her. She knew Kurt. She knew Kurt before she knew everyone else. When asked about it, they both said they met online two years ago and agreed to hang out the summer they met. They kept in touch regularly.

A third thing he knew, and this wasn't even really a big factor to Puck, but Quinn loved to throw this one out there. She was a girl of color. Pretty mocha skin, lush curls, hazel eyes that held a warmth to them when she looked at Finn. To everyone else, she was guarded, expect with Kurt. She was warm with Kurt. She was tiny too but her tininess only added onto her cuteness. Her skin color meant little to Puck, he liked her because of her personality and how she kept Finn on his toes.

She didn't belittle him. She lifted him up, even offered to help Puck with his grades. Shuester liked her because while she wasn't a member of glee club, she helped Finn with dancing and improving his range. Like right now, Puck sat as he watched Olivia play the piano. Finn loomed over her like the giant he was, his eyes bright as she hummed softly.

"Do you get it?" Olivia asked, stopping her playing.

"Yes I do," he answered.

She smiled and squeezed his hand. "Good," Olivia praised. That was another thing he noticed. Olivia praised him when he showed improvement. Finn leaned and sighed when her hand caressed his cheek. "Perhaps I should reward you tonight."

"Would you?" Finn asked. "Do I deserve it?"

Olivia frowned. "Those petty little dears really did ruin you, pup."

Pup. She always called Finn pup. Or dear. Darling too, but only when she was being really affectionate.

"I just thought-"

"I know you thought," Olivia said. Her voice was even, but Puck could hear an undertone of something else. She sighed when Finn winched at her tone. Her other hand came up and she cupped his face. "Finn, look at me."

He looked down at her through half lidded eyes. "Yes Olivia?"

"You don't need to ask me if you deserve it," she said. "You're improving greatly."

"Am I?"

"My dear you have a 3.5 GPA at the moment," she grinned. Puck's eyes shot up to his hairline. A 3.5 GPA? Holy shit, was this chick a fairy god girlfriend or something? He noticed Rachel and Quinn glaring at the couple from the doorway. Rachel's mouth dropped open when Olivia brought Finn closer and kissed the corner of his mouth, very close to his lips. It was the closest they all got to see them get this affectionate.

The two were very private; but ever once and awhile, there was always light touches or soft commands. Sometimes there would be praises and sometimes disappointments. The disappointments were rare though with Finn. Coach Beiste had seen grate improvement in his game.

"Aww look!" cried Brittany as she came into the choir room. "Finny and Livvy!"

Olivia turned towards the blonde. "Hello Brittany dear."

Brittany came over and kissed her cheeks. Olivia returned the favor. "Are you staying for practice?"

"I did promise Finn I'd stay to watch his practice today. I don't have work tonight."

Work, another thing they didn't know about her. She was a very private person. He knew she worked out of town, near the wealthier off. Rumors went around that she was a high end escort or private tutor. Kurt knew what she did but kept tight lipped. At the thought of Kurt, Puck turned his head towards the diva in mind. He was sitting with Sam, chatting it up as usual. He knew something was going on there. Sam had always been lovesick with Kurt, but he kept to himself. After Blaine broke up with Kurt in the summer because Kurt wouldn't just let loose, he had been single for a while. With Sam back, he and the diva had been closer than ever.

Puck knew Sam was set on dating Kurt. The only hallway declaration that happened upon Sam's return had brought of some almost bullying with the jocks. Sam had stood his ground though and Coach Sylvester was hellbent on tracking down all who tried to bully another student.

"Hello Olivia darling!" Kurt called as he came in. Olivia removed herself from Finn and giggled when Kurt lifted her up and spun her. He set her down, smoothing out her skirt and kissed both her cheeks. "You look exquisite as usual. I hope Finn's behaved himself."

His words were light and playful, like he was telling some inside joke.

"When isn't he?"

Puck seriously wanted to know what was going on there.

"Alright everyone, let's get started!" Shue called as he walked in the door. He beamed in Olivia's direction. "Hi there Olivia, joining us today?"

"Just watching," she answered. Everyone knew Shue had been trying to recruit her since Mercedes left. Olivia had declined over and over again. Everyone took their seats and Puck watched from his seat in the last row as Finn offered Olivia to sit in his normal chair. She declined, telling him. "Sit in your sit, pup."

"Where are you going to sit?" Santana asked.

Finn took his seat and his eyes widened as Olivia took a seat on his lap. She crossed her legs and wrapped an arm around his neck, her nails resting on the nape. That was a new one for everyone.

Except Kurt who was once again smirking in their direction.

"I'm comfortable here," she smiled and kissed Finn's jaw. "Aren't I pup?"

"Yes Olivia," he answered.

As rehearsal started Puck had come to a decision. He was going to uncover the mystery behind his best friend's girl.