A/N: A longish chapter. As the recent chapters are mostly about MommyPenny this one is DaddySheldon. Hehe.

Disclaimer: I don't own The Big Bang Theory.

Parenthood: The Final Frontier

Or Snapshots of the first five years of Isaac Cooper's life

Chapter Thirty-eight: Paging Doctor Cooper

The eight seconds it took for Cassie to stumble and to fall face first against the rough pavement of their backyard was the longest in Isaac short life.

It started as simple game of hide and seek. It was an ordinary day. Mommy left for a while to shop with Aunt Bernie and Aunt Amy. Daddy went inside for a moment to answer the phone. It left Isaac, Jimmy and Cassie playing in the backyard. Now Isaac loved hide and seek. He loved that he could quickly figure out where the others were and loved searching for new hiding places. Jimmy was okay with it and with Cassie already walking and talking they had enough players for it not to be boring. The two blondes nodded their assent when he suggested to play it. Isaac quickly explained the rules to his sister. She was a very smart girl and she got it the first time. And like always Jimmy insisted that Isaac be the seeker.

"Okay!" He agreed. "I'm going to count to thirty because this is Cassie's first game."

He leaned against the lone tree in their backyard. He covered his eyes and slowly counted. When he finished the place was deserted. Jimmy was a particularly good hider, so Isaac decided to search for him last. He rounded the area and caught the sound of soft giggling just at the side of the guest house. He walked towards that direction quietly.

"Found you!" He exclaimed, as he jumped around the corner. Cassie erupted to laughter, moving past him and urging her tiny legs to propel her faster towards the tree. Isaac could overtake her, of course, but that would be unfair because she was still small. He would just let her win for now. He jogged behind her then she suddenly she missed a step.

His heart pounded in his chest as adrenaline ran a quick course through vein. His brain was only chanting one word. Cassie. With a blink of an eye he was sprinting to the fallen form of his sister.

"Cassie! Cassie!" He called, helping her to sit down. There was smears of dirt all over her once pristine yellow shirt and her limbs. He brushed back her disheveled blonde hair back. He noted the scratch on her chubby cheeks and her watery blue green eyes.

"Hurts." She whispered, presenting him her hand. He looked down to see that the palm was scraped but not as badly as the skin of her knee. "Knee too."

"I know, Sweetie." He replied. That was how their mommy answered him when he tells her something hurts. Cassie sniffled, on the verge of tears.

"What happened?"

He glanced over his shoulder to look at Jimmy, who had left his hiding place. "Cassie fell down and injured herself."

"Oh." He examined the wounds. "You better call your Daddy."

Rationally, Isaac knew Jimmy was right. But he did not want to leave his sister alone and in pain. He was about to weigh the pros and cons when a hand landed on his shoulder. He looked at the grinning face of his best friend.

"Don't worry. I'll stay with her."

Isaac smiled and nodded. He trusted Jimmy. He would not let anymore bad thing to happen to his sister. "Okay." He gazed back at Cassie. "I'll call Daddy, just stay here."

"Quick." Was her answered.

Sheldon did not plan to be on the phone for more that three minutes. The children where unsupervised in their backyard and even though it was child proof twice over, accidents could still happen. But Gablehauser wanted a copy of his data for his refutation of Loop Quantum Gravity and that meant he had to go to his encrypted files and that meant more that three minutes. He just replaced the receiver to its cradle when the voice of his four year old filled the room.

"Daddy! Daddy! Come quickly," He said, clutching Sheldon's larger hand and dragging him to the direction of their backyard.

"Isaac, Isaac. Stop pulling me, darlin." At his endearment the boy stopped. He only called his son that when he wanted the little boy to calm down. Sheldon took that opportunity to lift him up. "Now tell me what happened."

"Cassie fell down Daddy. She scraped her knee and palm."

"Okay." Sheldon quickened his pace. In a few steps he and Isaac was outside and Sheldon immediately saw his daughter clutching her knee. Beside her was James Novel, who was murmuring reassurances. He let his son down and kneeled beside the little girl. Upon seeing him, Cassie finally let out her tears.

"There, there sweetheart. Daddy's here."

"Daddy, Cassie's hurt." She said, spreading her arms and non-verbally telling him to lift her up.

He obliged, of course, he brought her up and kissed her forehead. "Let's clean you up."

Sheldon walked towards the house, the two boys followed him both looking up to Cassie. worriedly.

"Mind where you're going Isaac." He said. "You too James. We don't want another accident."

"Yes Daddy." " Yes Doctor Cooper."

He put Cassie down the living room couch and left the two boys to accompany her as he quickly gather the supplies he needed. He was back in no time. He started by gently wiping the dirt off his daughter. From his periphery he caught Isaac climbing the sofa and holding Cassie's uninjured hand, he smiled at that. At his side he could feel James hovering and watching in interest. He started cleaning the little girls wounds, lightly dabbing them with a iodine soaked cotton ball. They were shallow and would not scar which was fortunate because Penny would 'freak out' if they did. He made quick work of the injuries. He had lots of practice as a child in these type of things.

"There." He said, with finality as he taped the last of the bandage on Cassie's cheek. "Good as new."

"Wow. You're really fast with that Doctor Cooper." James said, with awe.

"Why thank you James. If you must know, I've been treating wounds since I was your age."

"Will Cassie be okay, Daddy?"

He turned to his son, ruffling the boy's hair. "Of course, Isaac."

Cassie tilted her head at the bandage that was wrapped around her tiny hand. She looked at Sheldon with wide eyes. "Kiss it better, Daddy."

He smiled, bowing he kissed her bandaged knee, then her palm then lastly her cheek. "Now, how about some ice cream?"

The three children squealed in agreement.