The next day, Sheldon and Amy were enjoying a quiet day at home. The excitement from looking after Michael for the Wolowitz's had left them exhausted.

Penny and Leonard had tried to persuade them to go out with them but Sheldon and Amy were perfectly happy to sit at the kitchen island with warm mugs of tea and talk. Thus, the four of them had a day at home.

Unfortunately, another knock at the door soon put an end to their peace.

Leonard stood from his seat on the couch to open the door.

He stepped back in shock when a loud "Surprise!" was shouted from the other side.

Sheldon's twin sister Missy held her arms wide in the air and enveloped Leonard in a huge hug. Being much taller than him, Leonard was pressed forcibly into Missy's chest, although he did not complain.

"Leonard! And there's Penny!" Missy released Leonard and moved to wrap her arms around Penny.

Sheldon tutted from his seat in the kitchen. Missy spotted him and changed her target pathway.

"Shelly! Amy! How is the happy couple?" She teased as she walked over and placed a hand on each of their backs.

"What are you doing here?" Sheldon asked drearily.

"Now is that any way to greet your sister? I came to visit my little brother of course. And I may have also brought David and Johnathan with me" Missy's voice trailed off until her last sentence was almost a whisper.

Sheldon looked at her, appalled, "You brought your husband and son?"

"Yes. Come on, little Johnathan hasn't seen his uncle Shelly in months!"

"I told you, I am uncle Dr. Cooper" Sheldon rolled his eyes, "Where is he anyway?"

"David's bringing him up now"

As if on cue, Missy's husband drearily dragged himself through the open doorway of the apartment with a screaming toddler attached to his knee.

"Hiya all" His voice was dull and tired.

"Are you okay?" Penny asked.

"After a four-hour flight with this little guy? Yep I'm fine" David replied sarcastically.

"Well, if you'd like a break, we'd be happy to watch him for you whilst you catch up with Sheldon" Leonard offered.

"What are you doing?" Penny muttered under her breath to Leonard, not wanting to be stuck with the tearful toddler.

"Actually, I was kinda hoping that we might go out with you and Penny. Maybe give Johnathan some bonding time with his uncle" Missy looked hopefully towards them.

"Absolutely not" Sheldon shouted from the kitchen, "You can't abandon me alone with your son" He stood and marched over to the living room.

"Come on Sheldon, you won't be abandoned. I'll be here to help" Amy joined him and linked her fingers through his own.

Missy saw the way Sheldon's eyes softened and his hand clenched hold of hers for support.

"Great, then that's settled" Missy threw her arms up in excitement before kneeling down to talk to her son.

"Okay Johnny, uncle Sheldon and aunt Amy are going to look after you while Mommy and Daddy are gone. But don't worry, we'll be back soon. You'll have fun" She chuckled nervously. Her tone of voice was not as convincing as she had hoped.

With that, the two couples exited the apartment leaving Sheldon and Amy staring at the little boy with a moist upper lip, clammy hands and a trembling jaw.

Suddenly, he exploded into a torrent of wails and sobbing. He ran to the door and stood on his toes to try and reach the handle, "I want my mommy!" he gasped through the tears.

Sheldon desperately grabbed onto Amy's arm, "What do we do? Make it stop"

"Sheldon, he's a 'he' not an 'it'" Amy tutted and strolled over to Johnathan.

"Johnathan? Mommy will be back later but don't worry you can play with us" she said soothingly.

Johnathan turned away from the door to face her. He held up his arms and wiggled his fingers for Amy to pick him up. Once cradled in her arms, Johnathan leant his head against her shoulder and closed his eyes to recover from his previous outburst.

She carried him over to the kitchen and carefully placed him on a stool. Amy kept a hand on his back for support.

Sheldon was sitting opposite the toddler. Uncle and nephew studied each other intensely, never breaking eye contact.

Amy decided to break the silence, "Do you know what Uncle Sheldon's job is Johnny?" she asked, hoping this would attract the boy's attention.

Johnathan scrunched up his nose, mouth and forehead as if deep in thought. His soft blue eyes never leaving the bright azure opposite.

He finally spoke, proud of himself that he had remembered, "Rocket Scientist!" he replied with a wide smile. Despite being advanced in his class, Johnathan still had trouble forming his words. Often, 'R's would sound like 'W's and he occasionally missed the odd letter altogether.

Sheldon, who would normally pick his nephew up on mistakes, but was too distracted to notice the opportunity to correct his speech pattern.

Instead he looked up at Amy with his jaw hung wide open, "Did you hear that? A rocket scientist?" his voice broke in disbelief.

Amy sighed and bent low to Johnathan's head height, "Actually, he's a theoretical physicist"

"But mommy said-" the little boy began.

"Yeah well your 'mommy' barely understands wh-" Sheldon cut off his nephew, astonished that even after all these years his sister was still telling people he was a rocket scientist. However, Sheldon's rant had barely begun before Amy cut him off with a harsh stare.

"Sheldon!" She motioned her head towards the small boy who was sat staring blankly at his uncle.

"Hey Johnny, how would you like Uncle Sheldon to show you some science?" Amy asked, her tone rose high in excitement in an attempt to make Johnathan excited too.

In response, the toddler clapped his hands together and smiled, "Yes!"

Sheldon grinned smugly, always happy to show off his work. He jumped from his seat and began collecting his things together.

Amy was pleased her boyfriend actually looked eager to involve his nephew in his work. She lifted Johnathan and placed him on her lap so they could watch together. However, her glee soon turned grief as Sheldon rolled over a whiteboard and began scribbling numbers all over it.

Sheldon was speaking incredibly fast and writing recklessly. Even with her advanced understanding of physics, Amy was having a hard time keeping up. Johnathan was getting restless. He would not sit still and almost fell off Amy's lap.

"Sheldon, I think he's bored"

"How could he be bored. These are some incredibly advanced equations" Sheldon motioned towards his board, very proud of his level of work.

"I thought we were going to do more fun science. You know, the type that kids would like" Amy suggested.

"How is this not fun science?" Sheldon shook his head and replaced the cap on his pen, "I suppose we could do something more interactive. What do you have in mind?"

"I don't know, uh… we could make elephant's toothpaste?" Amy raised her eyebrows excitedly.

"What on earth is that?" Sheldon sighed.

"Surely you've done it. You mix hydrogen peroxide, warm water, soap and yeast to create an exothermic reaction"

"Ah yes. But where are we going to get some hydrogen peroxide?"

"I suppose I could run down to the drug store"

"And leave me here alone with him?"

"You could both come with me"

"I suppose that's the only option"

And so, Amy and Sheldon left apartment 4A, each holding the sticky hand of a toddler who skipped between them.

After a fairly uneventful journey, stopping only to chase a cat, the unconventional family arrived home.

Sheldon set up the experiment station in the kitchen with Johnathan keen to help.

Amy strolled away back to Sheldon's bedroom. She retrieved a t-shirt and returned to slip it over Johnathan's head.

"What do you think you're doing?" Sheldon was outraged to see his treasured clothes on a snotty little kid.

"It's just so he won't get his clothes dirty. We don't have any spares here" Amy snuggled up to Sheldon's arms and rested her head against his shoulder, "Besides, look how cute he looks"

The couple stood behind the island and watched their nephew. The t-shirt was far too big for him and scraped the floor. The sleeves, which were short and tight around Sheldon's biceps, were long and baggy on the child. Sheldon and Amy smiled at him. He did look cute.

Their adoration grew when Johnathan looked down at his chest and recognised the symbol embellished on it.

"Superman!" he shouted excitedly, pointing at the red letter S.

"Yes. Yes!" Sheldon beamed, "Do you like Superman?" Sheldon asked his nephew.

"Yeah" Johnny replied. He stuck a fist in the air and attempted to run in circles around the apartment but the t-shirt was far too long so he could not go very fast.

Amy laughed, "Okay, are you ready to make some elephant's toothpaste?" she asked, grabbing the toddler under the armpits and hoisting him back onto the chair. He sat on his knees with two hands on the counter top.

"What is it?" Johnathan asked.

"You'll soon find out" Sheldon replied mysteriously. He walked the little boy through the experiment, explaining how he was doing it and what each ingredient was.

"And finally, the yeast contains an enzyme that acts as a catalyst and…"

Sheldon poured the sachet of yeast into his concoction. Suddenly a plummet of foam exploded out, enveloping the entire kitchen. Johnathan squealed in delight and thrashed his hands into the froth to feel the bubbles. Sheldon and Amy grinned at his delight, glad that he had enjoyed their little science experiment.

"More! More!" he shouted.

Amy giggled, "Come on, let's play some more games whilst your Uncle cleans up this mess"

She winked at her boyfriend, took Johnny's hand and led him away towards the living room, leaving Sheldon looking peeved.


"That was a great evening, you guys should come and visit more often" Leonard smiled as they reached the third floor.

"Yeah, Leonard and I don't have any cool, young couples to hang out with" Penny said as they climbed yet another set of stairs.

"What about Sheldon and Amy?" David asked.

"I said 'cool'" Penny reiterated, causing a chuckle amongst her friends.

"Come on, Shelly's not that bad" Missy defended him, "Especially since he met Amy. Can you imagine what he was like as a kid?"

They finally reached the door to apartment 4A, inside they could hear a torrent of giggles and shrieks.

Looking at each other in confusion, they opened the door to see the scene inside.

The kitchen was covered in a thick froth that was bubbling from the island. It was dripping onto the floor and running down the counter.

However, that was not the most shocking spectacle.

Sheldon, fully dressed in his Flash costume was running around the apartment with Johnathan, still in the large Superman t-shirt, hoisted on his shoulders.

The toddler was in fits of giggles as he was bounced up and down. He clung to Sheldon who had a firm grip on his nephew's ankles.

Amy was adorned in Sheldon's green lantern t-shirt which was not as long as it was on Johnny, but still almost reached her knees. She was holding a small bowl of chocolates.

She was aiming the chocolates at Johnathan who was attempting to catch them in his mouth. Unfortunately, due to his laughter, most of them were hitting the floor.

"Flash, could you stand still? I can barely hit Superman with my kryptonite" Amy sighed dramatically.

"You'll never take him alive!" Sheldon shouted and began to run faster, spouting another fit of giggles from his nephew.

Sheldon paused, "Amy, I'm not really comfortable with this. The storyline makes no sense. Why would Green Lantern want to kill Super-"

Suddenly Amy jumped forward, "Ah-ha. Got you!", she held onto Sheldon's arm.

Penny, Leonard, Missy and David ambled into the apartment, shocked yet amused by the scene.

"My, my. What's going on here?" Missy put her hands on her hips and smiled at her brother, his girlfriend and her little boy.

"Mommy, we're playing superheroes!" Johnathan shouted down from Sheldon's shoulders.

"But apparently we are not conforming to the existing plots or franchises" Sheldon said sourly.

"I'm trying to attack them with chocolate kryptonite" Amy explained.

She jumped up and popped a chocolate into Johnny's mouth. He munched on it gratefully.

"Do I get a chocolate?" Sheldon asked, teasingly.

"No" Amy smirked, "But you do get this"

She stood on her toes and gently pressed her lips against his. Johnathan was too busy enjoying his chocolate to notice the saucy scene from his aunt and uncle.

The couple broke away and gleamed at each other.

"Now do I get a chocolate?" Sheldon taunted.

Amy took a chocolate from the bowl and threw it in the air.

With a swift head movement, Sheldon caught it on the tip of his tongue and crunched down.

He bent down, carefully to keep Johnny balanced and placed another chocolatey kiss on Amy's lips.