A/N: This is my first crossover FanFic! I don't know how many people will read this, but, too bad. This is dedicated to my best friend, who doesn't like fluff, and asked me to write a story with no fluff in it. To really understand this, you have to know that Kaley Cuoco plays both Bridget in 8 Simple Rules and Penny in Big Bang Theory.

DISCLAIMER: I DO NOT OWN 8 SIMPLE RULES OR BIG BANG THEORY.

Penny was walking across the hall towards Sheldon and Leonard's apartment when she ran into someone very familiar.

"Hi Bridget," She said

"Kerry? What are you doing here?" Penny hissed "and don't call me Bridget I go by Penny now."

"Why?" Kerry asked. Just then, a certain tall physicist walked out of the apartment opposite.

"Good evening Penny, I do hope your friend here won't be staying with you so I won't have to worry about the noise."

"No, Sheldon, she's just visiting."

"Oh, good. Anyway, I have to get my mail before Halo night starts."

"Who was that?" Kerry asked

"He's my neighbour." Penny told her. She pulled Kerry into her apartment "What are you doing here, anyway?" She growled

"Rory is sick. Very, very sick." Kerry said quietly

"Oh, no..." Penny said worriedly

Knock Knock Knock "Penny"

Knock Knock Knock "Penny"

Knock Knock Knock "Penny"

"Come in Sheldon." Penny said weakly

"Penny, I was just wondering- oh, you look distressed. Would you like me to leave?"

"No, it's fine. I just learned that my brother is really sick."

"I didn't know you had a brother! He lives in Nebraska?"

"No," Kerry answered, looking confused "He lives in Detroit."

"You never told us you had a brother in Detroit"

"Didn't she tell you?" Kerry asked "I'm her sister." she continued, sticking out her hand

"I'm sorry. I don't shake hands. Hands are ridden with bacteria and viruses." Sheldon told Kerry. She dropped her hand awkwardly "I'm Dr. Sheldon Cooper."

"Kerry Hennesey." She said

"Hennesey? But Penny's last name is Birch. And judging by the fact that you are not wearing a ring, I can assume you are not married."

"Sheldon, honey, Kerry's going to tell me what's wrong with Rory. Go back to your apartment. You're missing Halo night." Penny told him

**In Sheldon's apartment**

"Penny won't be joining us for Halo, her sister is visiting." Sheldon announced when he walked into the apartment

"Penny doesn't have a sister." Leonard said

"Apparently, she does, because she's there right now. And she has a brother." Sheldon said

"But why would she lie about having siblings?" Wolowitz asked

"Maybe she's embarrassed by them." Raj suggested

"I'm gonna go ask her." Leonard said as he was getting up.

Knock Knock Knock

"Come in!" Penny said, in a marginally better mood than when Sheldon left

"Hi, Penny." Leonard started "Sheldon was just telling us your sister had come to visit. Why didn't you tell us you had a sister?"

"Because Penny doesn't. Bridget does." She said, confusing everyone.

"Could you explain that please?" Leonard and Kerry said at the same time

"Leonard, go get the rest of the guys. It's time I told you everything."

A/N: How'd you like it so far? Review please!