Jack woke up in a hospital bed. He tried to sit up to see where he was, but he soon realized that he was unable to. His muscles were so sore, he could barely turn his head. What had happened last night? He couldn't even remember. He attempted to sit up again, but was met with pain and flashes of light before his eyes. Without even meaning to, he let out a small screech, and swung his legs over the side of the bed. He felt very disoriented, and fell off the cot. He gripped onto a counter and picked himself up, beginning to take a few steps. He had to find the Doctor.
The Doctor awoke with a start. He heard a scream, and raced down the TARDIS hall to the infirmary, which was currently inhabited by Rose and Jack. Last night, the Doctor realized that he hadn't slept for weeks, and even his superior Time Lord biology couldn't keep him awake anymore. He summoned his room next to the infirmary, and went to sleep, hoping his companions would be fine until the morning. He made out a shriek, and assumed one of the two was awake. But when he reached the infirmary, Jack's bed was empty, and a little boy stood in the doorway.
The Doctor stood frozen.
"Hello. I'm the Doctor. How did you get in here?"
The little boy's eyes widened in fear.
"Doctor?"
"Yes, that's me. Who are you?"
"Doctor, it's me."
The Doctor was stricken, and so was the boy.
"I'm sorry, but I've never seen you before in my life."
The Doctor pulled out his sonic screwdriver, and began the scan the boy standing in front of him. The child wanted to move, but he was completely immobile, in pain from head to toe. The Doctor completed his scan, and proceeded to checking the information.
Male. Ten years, four months. Human. Identity calculating... Calculating... Calculating...
The Doctor was growing impatient. He just wanted to know who the boy who stood motionless in front of him was.
Calculating... Calculating... Calculation inconclusive. DNA history scan calculates... Jack Harkness of the Boeshane Peninsula.
The Doctor looked from his screwdriver to the boy, from his screwdriver to the boy, many times before he decided to speak.
"Jack?" the Doctor asked the boy.
"Yes?" the boy answered the Doctor, in a mocking tone.
"I don't believe this. I do not believe this!"
The Doctor put his screwdriver away and knelt down to reach face to face with the boy.
"Captain Jack Harkness. No, I don't believe it."
"What don't you believe, Doctor?! Just tell me!"
The Doctor thought the boy looked hilarious, but then he saw that he was in pain.
"Jack, you have to stay calm after I tell you, do you promise?"
The child looked absolutely terrified, but nodded.
"You are approximately ten years old now."
The boy's eyes enlarged as he hobbled over to the mirror on the wall. He took one look at himself and rose his hands to his face. He started to cry.
"Doctor, what's going on? What happened?"
The Doctor drew his hand through his hair, and thought hard.
"I'm guessing it happened last night. The war? Do you remember it at all?"
A young Jack turned to face the Doctor.
"Sort of. It's really fuzzy. There was this man... And something happened, and the TARDIS showed up. It was really... painful."
The Doctor nodded.
"Yeah, that makes sense. You were probably shot, and that's why you were carrying Rose to the... Oh, Rose!"
The Doctor ran over to Rose's bed, and Jack limped behind him.
"What is it, Doctor? Is she okay?"
The Doctor went rigid when he reached her bedside. A little girl was now sleeping in the bed that Rose had occupied the night before. He took out his sonic screwdriver again and scanned her.
Female. Six years, five months. Human. Identity calculating... Calculating... Calculating... Calculation inconclusive. DNA history scan calculates... Rose Tyler of Earth.
The Doctor was blocking Jack's view of Rose, so Jack was unable to see her.
"Doctor? Doctor, is she alright? What's going on?"
The Doctor turned to Jack and put his index finger on his lips. Jack gave a knowing nod, and mouthed "oh", having realized that Rose, too, must have been de-aged.
"How old?" whispered Jack, as he followed the Doctor out of the infirmary.
"Six," replied the Doctor, once again running his hand through his hair. "Six and a bit. Still sleeping, I don't want to wake her."
The Doctor turned around when he felt a small tug at his pant leg.
"Doctor, I'm scared. What are we gonna do?"
The Doctor smiled to the boy, despite the fact that he was crying on the inside.
"I don't know, Jack. We'll figure it out. It can't be permanent, I can fix it. Don't worry, I will. But you do look so darn cute as a wittle itty bitty kid!"
The Doctor reached out to pinch his cheeks but Jack slapped his hand away.
"Hands off! I'm still Captian Jack Harkness, albeit being a little kid."
The Doctor grinned, and Jacked mirrored the smile.
"C'mon, Jack. Let's do a little research, shall we?"
Feeling better, Jack ran down the halls to catch up with the Doctor.