"Doctor, what is this?"
The Doctor turns around to see Clara standing near a pile of boxes in the TARDIS's enormous wardrobe holding up a small black pen. A fond smile grew quickly on his face before he excitedly said, "Well Clara that would be a sonic pen."
The warm smile on Clara's face shifted into a mischievous smirk. "Can I keep it?"
The Doctor laughed, "Of course you can."
Clara ran to the Doctor and hugged him tightly for a moment before skipping away from him. "So what does it do?"
"Well it can do the same things my screwdriver can do," he paused to frown for a moment, "it also can't do wood which I should do something about that."
Clara interrupted him before he could get lost in his rambling thoughts. "So where did you get it?"
The Doctor smiled sadly and ran a hand through his long brown hair. Clara frowned, she didn't mean to bring up any bad memories she was just curious. She flashed him a small, sympathetic smile. "You know what forget it. You don't have to tell me if you don't want to."
The Doctor shook his head. "No, it's okay." He sighed before a tiny, bright smile grew on his face. "It originally belonged to a nanny for the Adipose."
Clara tilted her head in confusion, "The Adipose?"
The Doctor chuckled warmly, "Adipose are a race made of fat. Anyway Matron Cofelia, the nanny, was using the inhabitants of England as surrogates for the Adipose because their breeding colony had gone missing. Unfortunately she also caught me and Donna snooping around and decided to speed up her plan by killing people."
Clara wanted to ask who Donna was, but it clicked that perhaps she was the cause for the Doctor's sadness earlier. So she settled for asking, "How would killing people help her speed up the breeding?
Doctor bounced with a goofy grin on his head. "Oh the Matron was clever, she had introduced the Adipose seeds to the human population as a diet pill. 'The fat just walks away' quite literally. Ah but me and Donna, partners in crime, did what we did best and saved the day, mostly. You know she found me. We were always destined to meet and she was destined to become the most important woman in the entire universe."
Clara felt a small jolt in her heart at the wistful expression and the soft, caring tone the Doctor used to describe Donna. She wanted to feel jealous, but any woman that could cause such affection in the Doctor must have been a magnificent woman. She shook herself lightly and gripped the pen a bit tighter. She looked around for a bit before aiming the pen at the air in a random location and pushed the button on it. She frowned when nothing happened and turned towards the Doctor. "Hey it's not working."
The Doctor frowned for a moment, snapping out of his memories, before responding. "It's been almost a hundred years since it was last used so it probably needs some maintenance." He took out his own sonic driver and aimed it at the pen until its blue tip glowed dimly. "Ah it just needs a bit of charging. We can charge it in the console, let's go Clara." Neither noticed the small flash of purple it emitted.
"Race you!" shouted Clara as she ran to the entrance of the TARDIS.
"No fair! You got a head start," shouted the pouting Doctor.
Clara smirked at the slightly panting alien that marched sullenly to the console in the center of the room. The Doctor ignored her in favor of looking for a port or some loose wires to charge the pen with. He fiddled with some wires before holding up the pen to show Clara and exclaiming, "Ah ha!" Their eyes grew wide as the TARDIS shook wildly.
"What's happening to the TARDIS Doctor?" screamed Clara as she clung to the stairs rail.
The Doctor shook his head, "There must have been something in the pen that is causing the TARDIS distress." His explanation was cut short when they stopped abruptly and all of the lights went out.
"Hello Spaceman."
The Doctor's eyes widened before he started looking around for the source of that familiar voice. Clara was about to ask him what was wrong when the image of a pretty red-headed woman in a grey dress with a brown leather jacket appeared in front of them.
Clara watched the Doctor's face slip into a sad, nostalgic visage.
"Donna," he whispered sadly.
The red-headed woman gave a sad but brilliant smile. "If you're seeing this Doctor it's because you couldn't find a way to stop me from burning out." Her smile turned into a fierce yet fond glare. "Erasing my memories of you does not count as a fix Spaceman! I know what you're like, you forget that I have your entire mind in me right now, and I bet that's exactly what you did."
The Doctor smiled guiltily as the projection sighed in exasperation.
Donna smirked with a puckish glint in her eyes as she waved the pen that had started this situation. "In any case I created this virus on the pen that would only be activated if you bleeped it with your screwdriver. I created a sub-wave emission that wouldn't interfere with the screwdrivers original function, only start up the pen."
Clara and the Doctor both smiled at the sass in her tone.
The smirk fell from Donna's face to be replaced by a sad frown. "Doctor I hope you're not travelling alone. Don't punish yourself with isolation. Besides I've met all of your companions and I'm sure you've made more. You should never be alone." The Doctor squeezed Clara's hand and gave her a small smile. "However, if you ever do find yourself alone, then I have prepared recordings with the help of the TARDIS of all of your companions. Be happy Doctor and remember that you are loved." She gifted them with a radiant smile before fading away.
Clara turned towards the Doctor. "Can I hear about your family?"
The Doctor grinned happily at her, "Of course Clara."