As the TARDIS flew through time and space toward planet Earth, the Doctor left Donna in the console room to look for Addi. He had a suspicion of where she had left to and found he was correct as he entered his former companion's room. There on the bed, Addi was curled up with dried tear stains on her cheeks. He sat next to her sleeping form and tried to gently rub the streaks of her face.
"You were right. It's not fair," he sighed. After a moment, he gently shook her shoulder and smiled when her eyes fluttered open. She didn't return it and he sighed once more, "I need you to come with me while I drop off Donna."
"Is that the bride?" Addi sat up, leaning back on one arm.
"Yes, I'm returning her to her wedding."
"Just leave me here," Addi frowned, laying back down and turning over.
"I will do no such thing, Addi," he gave her a stern stare even though she couldn't see it. " I refuse to let you be alone right now."
"I don't care!" She sat back up, "I don't want to do anything, I don't want to feel anything, I just want my family back!"
The Doctor just sighed once more, " I know, Addi. If i could bring them back, I would. But they wouldn't want you to waste away. Rose left you in my care, so let me take care of you while you go through this. We will grieve together."
Through all of the heartache and pain, a surge of gratitude radiated through her and she launched into his arms, mumbling a thank you into his neck. The Doctor hugged back just as tight, carrying her out of bed and back to the console room.
Setting her down in the singular chair, he started pulling some more levers, occasionally glancing at her to make sure she was still holding up. But, Addi was spaced out, once again staring at the wall of the TARDIS until a veil of white blocked her vision. Looking up, she saw the red-headed woman, Donna, glaring down at her in horror.
"Did he kidnap you too?"
"What?" Addi gaped. "I haven't been kidnapped."
Donna ignored her, spinning around to point an accusing finger at the Doctor, "So, you have kidnapped other girls! And this one clearly has Stockholm's!"
"What are you on about?" Addi stood, going up to block the Doctor from Donna's wrath. "He's my....brother-in-law?"
"He is?"
"I am?"
Addi kicked the Doctor in the shin, "He's with my older sister."
"I don't believe you," Donna stated, crossing her arms. Addi threw her own arms up in exasperation, going back to her chair.
A moment later, she had flown off as they landed. Donna rushed out as the Doctor helped Addi to her feet and dragged her outside after the bride. Addi whined about it, but allowed him to do so. They stopped next to Donna who frowned at the tall man.
"I said, St. Mary's. What sort of Martian are you? Where's this?"
Addi placed a hand on the side of the blue box, "Something's wrong with her. It's like she's sick."
The Doctor ran back inside and Addi followed. he ran around the console once and shouted to the woman outside, "Recalibrating! She's digesting." he began cooing to the TARDIS until Addi cleared her throat and gave him a pointed look. He shouted to Donna once again, "You've really got to think. Is there anything that might've caused this? Anything you might've done? Any sort of alien contact? I can't let you go wondering off. What if you're dangerous. I mean, have you- have you seen lights in the sky, or did you touch something, like something-something different, something strange? Or something made out of a- box of metal or- Who're you getting married to? Are you sure he's human? He's not a bit overweight with a zip around his forehead is he? Donna!"
Addi finished yawning at the Doctor's rant and jogged after his retreating figure, swinging the TARDIS doors closed behind her. Donna was stood on the side of the road, trying to hail a cab as the pair approached her.
"Donna-" The Doctor tried to get her to come back with them.
"Leave me alone. I just want to get married."
"Don't we all," Addi scoffed under her breath.
"Come back to the TARDIS," the Doctor tried.
"No way. That box is too weird."
"It's bigger on the inside, that's all."
Both Donna and Addi gave him stares of disbelief. Donna, stepping in front of Addi, "Oh! That's all? Ten past three, I'm going to miss it."
"You can phone them. Tell them where you are," Addi suggested, stepping toward the woman's side, instead of being behind her.
"How do I do that?" Donna asked them.
Addi opened her mouth to say something, but the Doctor cut her off, "Haven't you got a mobile?"
"I'm in my wedding dress," Donna spat back the man as Addi resisted the urge to facepalm. Donna carried on, "It doesn't have pockets. Who has pockets? Have you ever seen a bride with pockets? When I went to my fitting at Chez Alison, the once thing I forgot to say is 'give me pockets!'"
"This man you're marrying. What's his name?" The Doctor asked.
"Lance."
"Good luck, Lance," Both Addi and the Doctor chimed.
"Oi! No Stockholm's child and stupid Martian are going to stop me from getting married. To hell with both of you!" Donna ran away from them down the street.
"I'm- I'm not-I'm not- I'm not from Mars," the Doctor sighed.
"Well I'm not sick in the head either, but that isn't what matters right now is it?" Addi said, running off after the woman.
"Taxi!"
The yellow car drove past them without a glance and Addi crossed her arms with a grumble. Donna turned to the younger girl with a disgruntled pout, "Why's his light on?"
"There's another one!" The Doctor pointed out as another cab approached them.
"Oi!" The redhead screamed. Once again, no luck.
"Do you have this effect on everyone? Why aren't they stopping?" The Doctor question the bride.
"They think I'm in a fancy dress," Donna replied.
"Stay off the sauce, darling!" One of the passing drivers yelled out the window.
"They think you're drunk," Addi snorted.
"You're not fooling no one, mate!"
Donna's face dropping as she gave a mortified screech, "They think I'm in drag!"
Addi could no longer hold it together and burst out laughing, hunching over and clutching her stomach. The Doctor felt the weight on his shoulders lessen at the girl's bright giggles. Even Donna couldn't deny that the girl lit up like the sun when she was grinning- she'd only ever seen the girl frown or stare blankly at whatever was in front of her.
"Alright," Addi calmed down, "let me show you how it's done."
The small blonde let out an ear-piercing whistle and the taxi that had just passed them did a U turn, skidding to a halt right before them. Donna hopped in the back first, followed by Addi and then the Doctor.
"Saint Mary's in Chiswick, just off Hayden Road. It's an emergency. I'm getting married. Just hurry up!" Donna spouted out to the driver, who immediately stepped on the gas. Addi jolted back into the seat.
"You know it'll cost you, sweetheart?" The driver said over his shoulder. "Double rates today."
The three passengers froze in the backseat, realizing the situation they'd put themselves in. Donna turned to the other two, "Oh my God. Have you got any money?"
"Er...no. Haven't you?"
"Pockets!" Donna spat back at the man, before looking at Addi. "What about you?"
"I'm thirteen," the girl deadpanned.
The taxi stopped at the curb abruptly, sending Addi flying forward. The Doctor and Donna both placed their arms out to keep her from going any further than the backseat. They were then rudely told to get out of the car. Donna barely had both feet out of the vehicle before the man was speeding off again. The bride was shouting profanities at the top of her lungs and Addi took a few steps away so she wouldn't be associated with her.
"-talk about Christmas spirit." Donna finished.
"Is it Christmas?" The Doctor questioned.
"Well, duh. Maybe not on Mars, but here it's Christmas Eve."
The young girl froze hearing those words. She didn't register the Doctor dragging her toward a phone box or the conversation the other two were having. She was reliving all her Christmas memories with her family, and once again, she felt hollowed out. Why did it have to be Christmas right after she'd lost her mother and sister? Why'd she have to lose them in the first place? Where were the Doctor and Donna?
Spinning around, she spotted the Doctor stealing money from a nearby ATM and Donna hopping into a Taxi after taking cash from an old lady. The only thing she could do was blink in complete confusion.
Jogging over to the Doctor, she took the cash from his hand and patted him on the shoulder, "I think I'm gonna sit this one out, Doctor. I'm gonna get a taxi to a friend of my mum's and see if she'll do an estate sale of the flat."
He gave her a saddened, hesitant stare, "I don't know if that's a good idea, Addi."
"Please," she grabbed his hand, "I need to do this....I need time to grieve on my own."
A moment of silence passed between the two until finally the Doctor nodded, "Fine, but tell me where this friend lives so I know where to pick you up."
Addi gave him a small appreciative smile.
"It's on Baker Street."