Okay. I couldn't resist. One last Halloween story for my beloved Shenny. :)

Sheldon tilted his head and looked at the calendar again. There was no denying it. Penny was not normal. For twenty years he had been collecting data on the menstrual cycle of every female in his acquaintance. Mostly for self-preservation. Knowing when the women in his life were more likely to be highly emotional, and irrational was crucial to avoiding being yelled at, cried on, or throat punched.

The average menstrual cycle lasted 28 days, but could vary from 21 to 35 days. Almost every woman he kept track of had a fairly average cycle. He had a 93% accuracy rate, predicting each cycle within 3 days.

Penny was the only exception to that. Penny's cycle began every 29 days, exactly. There was no variation in her menses. He had four years of data to back this up. Penny's cycle was an aberration.

Sheldon could not tolerate not knowing something. He had to figure out what made Penny different. The first thing to do was to catalog every routine Penny had. From that he could form a working theory on what made her unique.

Sheldon looked over his notes with a frustrated sigh. How could one woman be so chaotic? He had spent five months studying every move Penny made. There was absolutely no pattern to her life! She worked different shifts every week. She shopped at different times. She slept in random patterns, seemingly resting whenever the urge hit. Eating, cleaning (if you could call what she did 'cleaning'), jogging, even watching TV. It was all randomly done. She didn't even go to the bathroom on schedule!

He ran a frustrated hand through his hair. Her menses was the one and ONLY pattern in her life! Every 29 days Penny would go on a two night trip. She claimed she was visiting a spa for stress relief. However, when he called the spa to speak to her, they had no record of her being there. He had hacked the spa's records and discovered that Penny had never been a guest.

She had lied to them. For years, she had been lying about where she went and why. Sheldon looked at his calendar and sighed. Penny's pattern would start again in two days. He would need to follow her and discover the secret to Penny's cycle. He was going to need taxi pants for this.

Sheldon whimpered as he pressed hard on the wound on his calf. There wasn't much space behind the furnace, but he managed to squeeze himself into it. Warm spittle flew at him from the snapping jaws just inches away. Claws snagged the cuff of his pants and ripped a large hole in them. He tried to make himself as small as possible.

He stared at the wolf with fear. It's thick fur was the color of wheat. The eyes were still hazel green, but empty of personality. Animal eyes. He licked his lips nervously. "Penny? Are you in there?"

The wolf went crazy, attacking in a frenzy. He curled up into an even tighter ball and closed his eyes. He covered his ears with his hands and tried to block the snarls out. "Soft kitty, warm kitty, little ball of fur." He sang to himself loudly over and over to drown out the wolf.

Sheldon could smell bacon. Slowly he opened his eyes. What a weird dream! He sat up and froze when he realized he wasn't in his bedroom. The cabin walls were bare. There was a thick blanket over the window, blocking out the sunlight. He was lying on an old couch, still in his torn and bloody chinos. His Flash shirt was missing, but he still wore his long sleeved blue thermal.

"Breakfast is almost ready."

He looked around quickly, finding Penny standing in front of the stove, her back to him. He was surprised to see her wearing his shirt. It barely covered her bottom. He stood up carefully, expecting to feel pain in his leg.

"You healed," she told him softly. She turned to face him, tears in her eyes. "Dammit, Moon Pie! Why did you follow me?"

He shuffled awkwardly. "This is a dream, right? Tell me this is a dream, Penny."

Penny looked away, brushing a hand across her eyes.

Sheldon looked around the small cabin he had followed her to. It was an hour outside of Pasadena, near a national park. A couch, a small TV with a DVD player sitting on the floor, the furnace, a stove, a shower stall, and a fridge were the sum total of furnishings. There were five deadbolts on the door, deep claw marks revealing the steel core under the wood.

"I was nine when my mom went out one evening," Penny said softly. "One of our horses was stuck in a mud pit. She was trying to get it free. She got attacked. By the time she got back to the farm, her wounds were gone. She convinced herself it was just a nightmare. The next month, she changed. Luckily, Dad and sis were away, driving my brother to rehab. She attacked me."

Sheldon sat down on the couch, his mind struggling to absorb Penny's story. "So, your mom was attacked by a werewolf, and she in turn, made you one."

Penny looked at him with sorrow. "And now I've made you one," she whispered.

Darkness edged around his vision. It was too much for him to process.

Sheldon groaned as he woke up again. The smell of bacon and eggs hit him hard. His stomach growled loudly.

"Come eat," Penny said softly. "You need the carbs."

He hesitated for a moment, but his stomach growled again. He took the plate she held out and looked around. "Are you not eating?"

She blushed and looked away. "I already ate. My food didn't require as much…preparation."

He swallowed nervously. "Raw?"

She nodded with embarrassment. He took a few bites, savoring the taste. The bacon was perfect and the eggs were delicious. Even better than the ones he made when he was trying to perfect the recipe years ago.

He chewed carefully, thinking about everything she had said earlier. "How do you know I will turn?" She sighed and sat down beside him. He couldn't help noticing how his shirt rode up her hips, revealing white panties. He felt his pulse rate increase a bit.

"I can feel it," she said softly. "I don't know how else to explain it to you, but I can feel the energy of your wolf."

He finished his breakfast and set aside the plate. He had to admit he was feeling a bit different. More… energized. He expected to panic, or feel frightened. Instead, he only felt calm. "Wait! There was no full moon last night. The full moon won't come around for another week."

She shrugged casually. "Myth. My wolf isn't tied to the moon. She's tied to when I was bit. 29 days after that happened I changed. It has nothing to do with the moon."

He looked at her with confusion. "So in 29 days I will change?"

"Yep," Penny answered. "I'm so sorry, Sheldon. I never wanted this to happen." Penny yawned widely and slumped down on the couch a bit more.

Sheldon grabbed the thin blanket off the back of the couch and unfolded it. "You are tired. You should get some rest," he said gently. "I suppose I should leave before you turn again."

Penny's eyes drifted closed. "No worries," she mumbled. "My wolf recognizes yours. I won't attack again."

Sheldon watched her fall asleep. After a few minutes he rearranged her so her head was on his lap. He turned on the small TV and found a marathon of Twilight Zone episodes. His right hand moved in a continuous motion, smoothing her hair.

It was almost noon when his phone rang. He looked at the screen, frowning when he saw Leonard's name. He glanced at Penny and accepted the call. "Hello, Leonard. Why are you calling?"

"Where the hell are you?" Leonard demanded. "Amy wants to call the police and report you missing. She is insisting we need to put your face on milk cartons. You missed laundry night, you know."

Sheldon looked at Penny, sleeping so serenely. He considered telling Leonard he was working and would return when he was done. Leonard wouldn't be able to tell over the phone that he was lying. Then a surge of aggressiveness hit him. "I am fine, Leonard. Penny and I will return tomorrow, possibly. Maybe the next day. We shall have to wait and see."

There was silence on the other end for several seconds. Sheldon pulled the phone from his ear to see if Leonard had hung up.

"What do you mean you and Penny will return tomorrow?" Leonard screamed. "Where are you? What are you doing? Why are you with Penny?! Put her on the phone, right freakin' now!"

Sheldon caressed Penny's cheek. "Not possible," he said calmly. "She is asleep at the moment. We were both up quite late."

"What the hell does that mean?" Leonard demanded. "What is going on with you and Penny?"

Sheldon decided, fairly quickly, that although there would likely be very painful consequences later, he was tired of Leonard trying to renew a carnal relationship with his Penny. "As I said, Leonard, Penny and I are away for the weekend. We will return either tomorrow or Monday. As for what that means, it is very simple. Penny and I are together. We have formed a pair-bond. Please inform my girl-slash-friend, Amy Farrah Fowler, that I am well and there is no need to report me missing. Now, please excuse me, I intend to catch a little sleep before Penny awakens."

Sheldon hung up and carefully maneuvered him and Penny around until they were both stretched out on the couch. He wrapped an arm around her securely and closed his eyes. She was likely to punch him when she found out, but he did not regret misleading Leonard.

The night went by too fast for Sheldon. He woke up at dusk to the sound of Penny shifting into her wolf form. He watched in amazement as her bones rearranged themselves and golden fur sprang free. Her claws burst from her middle knuckles while the tips of her fingers curled inwards and became the pads of her paws. Most impressive was the look of joy and exhilaration in her eyes as she changed.

The rest of the night was spent with her either clawing at the door for release, sitting in front of him with her muzzle resting on his lap or sleeping on the couch beside him.

At one point Penny had been sound asleep, whimpering, with one leg kicking slightly. What did werewolves dream of, he wondered. Moons? Chasing people? Chasing cars? He would have to ask her when she returned to being Penny.

As for him personally, he felt edgy all night, like his skin was too tight. He was certain that Penny was right. He would change into a wolf next time. He actually wished he could change now. He was eager to experience it for himself.

Around 4 am he began to tire again and fell into a light sleep. When he woke up again, the sun was up and Penny was laying on top of him, sound asleep. His first thought was to slide out from under her and put some distance between them. A second later that thought evaporated as Penny squirmed to get more comfortable.

Sheldon slid his hands down her back to her hips. He kneaded gently and pressed against her harder. Penny moaned softly, her hips wiggling a bit. She turned her head and nuzzled at his neck.

"Penny? Are you awake?" he managed to gasp out. He couldn't stop himself from bucking his hips into her.

"Sheldon?" she mumbled. "Am I dreaming?"

He groaned out loud. "If you are, then I am. Don't wake us."

Penny raised her head and looked at him with desire filled eyes. "Sheldon, you don't like being touched."

He brought his hands up and cupped her face. "I want to touch you." He didn't wait for an answer. He pulled her closer and kissed her, over and over.

At some point they rolled off the couch onto the floor. He abandoned her lips and turned his attention to her breasts. They were beautiful. He caressed them gently. Penny's hands ran under his shirts, pushing them up his chest. He whipped it over his head to get it out of the way quickly. He growled as she wrapped her legs around his waist and rubbed against his erection.

Penny froze at the sound of his growl. Sheldon looked down at her with confusion. "What? What is wrong?" he asked.

"Holy crap," she whispered. "Oh god, Moon Pie! You're my alpha!"

He raised up onto his knees. "Is that a bad thing? Please tell me that it's not a bad thing, Penny."

Slowly Penny sat up. Her eyes were wide. "I've been a wolf for 17 years, Sheldon. I've met male werewolves before. But I was never drawn to any of them. I just figured I was a loner."

Sheldon swallowed nervously. "You said I'm your alpha. What does that mean?"

Penny placed a hand over his heart. She picked up his hand and placed it over hers. "Can you feel that? Our hearts are beating in sync. You are touching me without your usual phobias. The lust between us. It's because we're a pair. Wolf packs are usually led by an alpha male. If we bond, you would be my alpha."

Sheldon thought through what she was saying, automatically comparing it to what he knew of the animal kingdom. "We would be a couple."

Penny nodded hesitantly. "Werewolves mate for life, Sheldon. If we do this, if we… consummate…"

"You and I would bond romantically. For life," he finished for her.

Penny nodded, biting her bottom lip nervously. "Sheldon, I don't want to force anything on you. I don't want you to regret anything."

Sheldon leaned forward quickly and kissed Penny. "I want this," he said huskily. "Penny, whatever this is, whatever being a werewolf has done to both of us, I cannot deny that it feels right. I know it's not all the wolf, either. Penny, you are my best friend. You are the one I rely on and trust whole-heartedly. You have always been special to me."

He kissed her again, making Penny moan softly. "I truly want this," he assured her.

Penny's hands had his chinos unzipped and pushed off his hips in the time it took him to take a deep breath. He picked her up and rolled over so she rose above him. He slid inside her, gasping with pleasure. Penny placed her hands on his chest and settled her hips against his.

Sheldon knew there was more to sex than this, but damned if he could remember what it was. All he could think about was how incredible it felt to be buried so deeply inside Penny. His hands gripped her waist tightly as he tried not to ejaculate immediately.

Penny leaned forward and gently kissed him. "Are you with me?" she asked.

Sheldon swallowed nervously and nodded. "Yes, always."

Penny moved slowly, rising and falling in a steady rhythm. Each shift in her hips made Sheldon's heart beat harder. He released her hips and trailed his hands up her sides to her shoulders. He pulled her down so he could capture her lips again. He began to move his own hips, meeting her thrust for thrust.

As their lips teased and coaxed one another, they could feel the bond between them strengthen. Their bodies moved in unison, instincts as old as time driving them.

Penny sat up, and looked at him with smoldering eyes. "Say it."

Sheldon rolled them over, thrusting deeply. He had no idea where the words came from. They just bubbled up inside him. "You are mine," he growled. "My mate. My bonded. The other half of me."

Penny smiled widely. "I am yours. My alpha. My bonded."

Both of them shuddered as their orgasms hit. It was made all the more powerful as the bond between them finalize, tying them together, heart and soul. Sheldon slumped to the side, drawing Penny close. He tiredly kissed her forehead as they both began to drift off to sleep.

"Love you," Penny whispered.

"Love you," he whispered back.

Leonard tried to start an argument when they finally returned home. Penny would have stepped in and stopped it, but Sheldon pinning Leonard to the wall beside the bathroom door shut Leonard up quite effectively.

Amy was a bit disgruntled, at first, to find her time with Sheldon reduced. Sheldon was her only friend and she was reluctant to relinquish time with him. Then Penny took the brunette out for a few drinks and introduced her to Zack.

As for their other friends, it took them a little while to grow accustomed to Sheldon and Penny as a couple, but in all honesty, none of them were really all that surprised. Sheldon and Penny had always sparked off one another. Besides, they thought it was cute the way the two of them took off every 29 days for a lover's retreat.