A/N: I suppose spoilers for S2 E6, since it mentions Ramona, and has a similar base plot line.

Early Tuesday morning, Penny quietly opened the door to 4A, and began walking towards the kitchen. A few steps in she noticed a mid-twenties girl lying on the couch. She paused and looked at her for a few seconds, before shrugging her shoulders and continuing towards the kitchen. Who knew what Sheldon or one of the other guys was up to.

She would ask Sheldon when he got up, which should be in a few minutes according to the time on her phone before she'd walked in. She made it a few more steps before she accidentally ran into Sheldon's desk. Penny tried to muffle her swearing, but the girl had already startled awake, and was staring at her as she covered the rest of the distance to the fridge.

"Who are you and what are you doing here?!"

"Penny. And I'm out of milk," Penny replied, opening the refrigerator door and grabbing the milk.

Before Ella could respond, they heard Sheldon from the hallway; "I don't think intentionally not going to the grocery store when you know you don't have any food counts as 'being out of milk'."

"So maybe I've ran out of milk a few times this week."

"You've eaten every meal when you weren't at the Cheesecake Factory here since Leonard left on his vacation."

"Really? Are you sure?" Penny responded, looking up at him.

"What is she doing here?!" interrupted Ella.

"I thought that would be fairly obvious," replied Sheldon, getting a bowl out of the cabinet. Turning back to Penny he said, "Can't you at least put the milk back in fridge after you use it? It's bad enough that you steal my food, without letting it spoil as well."

"Yeah, yeah, I'll try to remember," she said waving him off. "Who's the chick sleeping on your couch?" she asked, pointing over her shoulder to where the girl was sitting in Penny's spot on the couch.

"That is Ella, a PhD candidate at CalTech. She is writing her thesis on string theory, and since I am the foremost authority in the field, she came to me for help."

"That's nice," mumbled Penny, having stopped paying attention after 'PhD candidate'. She still remembered when Ramona had briefly crashed into their lives. "Are you still coming to the Cheesecake Factory tonight, even though the other guys are out of town?"

"Penny, it's Tuesday," he replied in his condescending voice.

"Is anyone going to tell me who she is?" interrupted Ella once again.

They both turned and looked at Ella.

"This is Penny, who lives in the apartment across the hall," replied Sheldon.

"Then why is she over here at seven in the morning, in her underwear, eating your food!" Ella was practically yelling by this point.

At the words 'in her underwear', Penny instinctively looked down at the tank top and shorts she was wearing. It was actually rather modest compared to what she waltzed over in sometimes.

"Because she doesn't have any— Wait, why are you here so early?" he said, turning to look at her. "Your shift isn't until this afternoon, you usually don't drag in here demanding milk for your coffee, which you've started making over here instead of bringing your own, by the way, don't think I haven't noticed, for at least another hour."

Before Penny could answer, Ella spoke up again. "Are you sleeping with him?" she practically growled, glaring at Penny.

Penny burst out laughing, nearly falling out of her chair. "Me and Sheldon sleeping together?" she choked out in between laughs. "Absolutely no way."

"Why would we be sharing a bed?" asked Sheldon in confusion at the same time. "She lives just across the hall."

"Oh sweetie, I'll explain what she means later," she said, patting him lightly on the arm. Turning back to Ella, she continued, "we aren't dating or anything. I just live across the hall and eat all of their food," as if that explained everything. But Ella wasn't buying it. Penny finished her breakfast in silence as Ella continued to glare at her.

Penny made a mental note to ask Sheldon how long this girl would be staying in his apartment when he came to the Cheesecake Factory that evening.

Once she finished eating, she turned to Sheldon, who was contentedly eating his own cereal in the seat next to her, and said, "I assume she's your ride to work, because I have an audition this morning I have to get to."

"Ah, so that would be why you are up earlier than your usual time this morning." Penny nodded her head. "And yes, Ella will be driving me to work."

"Well, have a good day at work," she said, as she pushed her bowl towards the sink, and got out of her chair, briefly touching his arm with her hand as she turned towards the door. "Bye Ella," she added in a sing-song voice as she walked over to the door and headed to her own apartment.

That evening, when Penny brought Sheldon his drink, she asked him, "So why is this Ph.D. candidate staying in your apartment?"

"She volunteered to bring supper in exchange for my expertise in String Theory. And since you were working late and couldn't bring supper, I said yes. And then she apparently stayed after I went to bed."

"She staying for long?"

"How would I know? I didn't invite her to stay in the first place," he objected.

Oh, poor Sheldon. Did he not learn with Romana?

When she brought him his burger, he asked, "How did your audition go this morning?"

Leaning against the back of the chair opposite of him, Penny regaled him with the details of her audition. She knew he didn't really care, that he was only asking because he considered it a Non-Optional Social Convention, but she was happy nonetheless that he asked.

As she began to transition from her audition to her work shift, Sheldon cut her off; "Don't you have other tables to wait on?"

"Right, Sweetie, I suppose I do. I'll be back around in a while if you need anything else," she said as she stood up and started to leave.

After he finished, she brought him his weekly cheesecake; the only thing in his weekly diet other than Anything-Can-Happen-Thursday that he didn't eat exactly the same thing every time. After a lengthy argument, several threats of blackmail, and vigorous promises that every type of cheesecake was prepared with the same level of sanitariness and that she would see to it that it was upheld, Sheldon had finally given into Penny's begging that he try other cheesecakes besides the super-chocolate cheesecake that he personally watched them make the first time he tried it. And now, much to Leonard's annoyance, Penny brought him a different flavored cheesecake each week.

"So," she said, leaning on the back of the chair across from him again, "I just got the bluray of 'Star Trek: Into Darkness', and was wondering if you wanted to come over tomorrow for supper and to watch it." As Sheldon began to open his mouth to protest, she added, "I'll get your regular Chinese order, and we'll be done with the movie in time to go to the comic book store."

After some indistinct grumbling about it not being at his apartment, Sheldon agreed.

The following afternoon, as soon as Ella parked at the apartment, Sheldon exited the car and headed upstairs, straight for Penny's apartment. Penny, who had just arrived with their take-out, paused on the third floor landing as she heard Sheldon's footsteps coming up the stairs, and waited for him to catch up to her.

A minute later, when Ella reached the fourth floor, they had already disappeared into Penny's apartment. Ella strode into 4A, assuming Sheldon was already inside. When she didn't see him, she assumed he was in his bedroom or in the bathroom, and so settled into the middle cushion of the couch to wait on him.

After a while, she realized she still hadn't seem him, so she got off the couch and started to look for him. She had checked both his room and the bathroom when she remembered something; that blonde slut that she didn't trust, Sheldon had said she lived across the hall.

Ella stormed across the hall and pounded on the door; "PENNY!"

Meanwhile, across the hall, Penny and Sheldon had finished supper, and were partway through 'Into Darkness'. Their empty takeout containers were sitting on the coffee table, and sometime after they had finished eating, Penny had tucked her feet up under her and leaned against Sheldon's shoulder. The lights were dim because it had been light enough outside when they got in that Penny hadn't bothered flipping the living room light on, but now that the sun was starting to set, the measly kitchen light didn't provide much in the way of brightness. But since they were just watching a movie, Penny hadn't bothered getting up to flip on the living room light.

At the sound of pounding on Penny's door, Sheldon jumped slightly. At the end of the knocking, they heard Ella shout Penny's name.

"Oh look, your grad student finally noticed you were missing," Penny said quietly to Sheldon, before yelling, "It's open."

Ella opened the door and froze, taking in the scene before her. Penny knew what was going through Ella's mind, even if Sheldon didn't, but she wasn't in any hurry to set the record straight.

"You shameless little hussy!" was the first thing to escape from Ella's mouth.

Penny briefly glanced over at Ella before returning her attention back to Kirk, Spock, and Benedict Cumberbatch (ok, ok, Kahn, or something like that, but who really cared, it was Benedict Frickin Cumberbatch). "Oh, are you dating Sheldon? I didn't know that."

Ella fumed for a few seconds, before slamming the door shut and stomping back across the hall.

Once she was gone, Sheldon opened his mouth; "Why did you ask if she was dating me? You know I'm not dating her."

"Yes, Sweetie, I know that, but Ella is acting as if I'm somehow cheating on her by being friends with you. I was just casually pointing out that she has no reason to be mad that we're friends."

The following day, Penny didn't see Sheldon at all. She assumed that Ella had him trapped away, but since he hadn't come panickedly knocking at her door yet, she hadn't gone looking for him. He was eventually going to have to learn how to deal with these girls on his own.

As she was about to climb into bed that night, she noticed a large puddle of water on her bed. Looking up at the ceiling above her bed, she saw that it was dripping a steady stream of water. Softly cursing to herself, she went into her kitchen to grab some pans to place under the drips. The building manager would be getting an earful in the morning.

But in the meantime, she had to figure out where to sleep. She took one look at her couch, and knew that wasn't happening. She had enough clothes and other crap piled on it to start her own store, and given the already dreadful state of her floor, pushing everything off the couch onto the floor would probably give Sheldon a heart attack if he saw it. So she did the only thing left, and grabbed her emergency key and walked across the hall.

She really must have been tired, because it wasn't until she entered 4A that she remembered that he already had a houseguest sleeping on his couch. Looking at Ella, she had a sudden urge to push her off the couch and claim it as her rightful own. But the ensuing cat-fight would wake up Sheldon, so instead, she kept walking.

She quietly opened his door and shut it behind her, before climbing into his bed. As soon as she put her weight on the bed, he shot up into a sitting position, shouting "Danger, Danger!". Penny ignored him and turned on her side facing away from him, adjusting the covers around her.

"Penny, people can't be in my bedroom."

"There's a water leak directly above my bed, and your couch is taken."

"Why don't you sleep in Leonard's room?"

"Ewe, no."

"Penny, you can't be here."

"Go to sleep Sheldon. I'm not moving unless you go kick your grad student off the couch, and that would require getting out of bed after you've already gotten in bed."

He seriously contemplated the idea, before resorting to, "I'll give you three strikes and banish you from the apartment." He tried his hardest to sound threatening, but it came out as more of a whine than a command.

She just reached behind her and patted his knee, and replied, "In the morning, Sweetie. In the morning."

When Sheldon woke the next morning, he briefly thought part of the ceiling had caved in overnight and was lying on his chest. But then he remembered that ceilings typically do not have long, flowing, golden hair. Certain across the hall neighbors with no understanding of personal boundaries, on the other hand, did.

Tap, tap, tap, "Penny"
Tap, tap, tap, "Penny"
Tap, tap, tap, "Penny," he whispered.

"Morning Sheldon," she replied sleepily.

As she failed to move, he resumed poking her.

"Still going to give me those strikes and banish me from the apartment?" she smirked into his chest.

"If you don't get off of me so that I can get ready for work," he replied, but without any of his usual bite.

Penny reluctantly rolled off of him onto her back, with a long, exaggerated sigh. "You're no fun."

"How is not giving you the strikes and banishment you so very much deserve 'no fun'?" he asked, confused.

"No, not that," she responded, vaguely waving a hand in the air, her eyes still closed. "You're no fun to wake up in bed with."

He simply glared at her for a few seconds, before grabbing his Friday clothes and heading to the bathroom.

After Penny heard the shower start, she finally opened her eyes and got up. Even being Sheldon, and repeatedly poking her, she had to admit that he was still one of the nicer guys she'd ever woken up next to. He at least wasn't kicking her out, or she wasn't trying to kick him out. And being Sheldon, he'd handled waking up with her using his chest as a pillow rather well. She wandered out of his bedroom and into the kitchen.

Ella had woken up when she heard the shower start, and was in the process of pouring Sheldon's cereal.

"He has oatmeal on Fridays."

She looked up and saw Penny strolling in from the hallway, in a similar tank top and shorts to the one she'd been wearing the first day she saw her.

"Where did you come from?!" Ella asked in shock.

"Sheldon's room," she answered nonchalantly, before beginning to round up the ingredients for French Toast. She knew Sheldon wouldn't eat any, but she still wanted some. It had become something of a routine or her own to have French Toast the morning after sleeping with a guy she wasn't trying to get rid of, and while sharing a bed with Sheldon certainly didn't meet the normal requirements of "sleeping with a guy", she had technically slept with him, so she was having French Toast.

She had just finished putting the last piece of French Toast on her plate when Sheldon walked in.

"I fail to see why you're having French Toast this morning, you didn't have coitus with anyone last night."

Penny looked up at him in shock.

"You have French Toast the mornings after you've slept with a guy you didn't then kick out," he explained as she stared at him.

"How on earth do you know that!? And anyway, it's after I sleep with a guy, and I did sleep with a guy last night."

"You have never made them after merely sharing a bed with a guy before. Then again, I suppose you have never shared a bed with a guy before without having coitus, so it's rather a mute argument."

"First off, it's called sex, and secondly…okay, that part you're kind of right about."

Meanwhile, Ella had been staring back and forth between the two of them during the whole conversation. "You two seriously slept together?" she asked when they finished.

"Yep," replied Penny, popping the 'p'.

"That's it, I'm out of here! Have fun with your girlfriend, you sluts!" And with that, she stormed out of the apartment, slamming the door behind her.

Penny turned and looked at Sheldon. "So, MoonPie, doing anything after work?"