It all starts one fine morning in the Golden Oak Library. Spike is cleaning upstairs, looking in old boxes, when he gets to the last one.
"Oh yeah! Last box!", he says.
Spike opens the lid and starts to pull things out.
"Lots of old junk in here," says Spike.
Spike pulls out an old rattle Twilight had as a filly, which he surprisingly remembers playing with a while back.
"Twilight's old rattle," he mutters while taking a look at it and shaking it.
Spike then puts the rattle down and continues to make tow piles, one for trash and one with almost all of the contents to ask Twilight about. Finally, Spike reaches the bottom and sees a scrap of paper.
"What's this?", he wonders out loud.
He did not think he would find a little piece of paper at the very end of this box. Spike picks it up and turns it over, coming face to face with a young light purple dragon smiling widely at him.
"Aah!", Spike yells, startled.
He was not at all expecting there to be a dragon on the front picture looking right at him in the face. He drops the picture in shock at how much the dragon looks just like him, albeit a slightly longer nose and a longer, thinner face. He scans the picture and finds a pencil marking on the bottom saying, "Derek." Spike continues to stare at the picture in his claws for a few minutes before shaking his head and standing up.
"I need to ask Twilight about this," he declares, wanting to know once and for all exactly who this dragon is.
Spike walks down the steps, finding Twilight re-organizing all of the books.
"Hey, Twilight," Spike greeted.
"Hey, Spike. What's up?", says Twilight.
"Well, I was wondering who this is," Spike says.
"Who's who?", Twilight asks.
Spike walks over to Twilight and shows her the picture. Twilight sets down the book she is holding and takes the picture with her magic.
"Oh, that's Derek," Twilight says, immediately recognizing the dragon in the picture.
"Yeah, I figured that out," retorts Spike, raising an eyebrow. "But who exactly is he and why does he look like me?"
Twilight continues to look at the picture, smiling and a bit of sadness in her eyes. She must have known this dragon sometime ago.
"He was my assistant when I was a filly. And I mean even before you. My parents found him when I was about 3 and I just kind of grew up with him always helping me," Twilight explains to Spike.
"Oh," says Spike. He is shocked to hear that there was ever another dragon who was first before himself. This whole entire time, he had been thinking he was her first. Since Derek is first, this would mean that Spike was really her #2 assistant all along this whole time. Now upon hearing this news, Spike no longer feels so special. "What happened to him?", Spike asks Twilight.
Twilight's smile fades as she sets the picture down and looks at Spike.
She explains, "He eventually moved away when I hatched you because I guess he felt like he'd be replaced, just like when you thought Owlowiscious would replace you."
Spike looks up at Twilight, starting to see tears in her eyes. He begins to regret asking her about Derek. Seeing Twilight upset is one of the worst things he could possibly see. Plus, he did not think she would start crying.
"Oh. I'm sorry. I didn't know," Spike apologizes.
Twilight wipes away her tears and wraps her hooves around Spike, pulling him into a warm hug. She smiles sadly.
"It's all right, Spike. I'm just glad I have you."
Twilight rests her chin on Spike's head. Spike pats her hoof gently in a comforting manner.
"I'm sorry he left. He missed out on a lot of great times," says Spike.
Twilight chuckles, already starting to feel her sadness subside. After a few minutes, Spike pulls away slowly and looks up at Twilight.
"So you haven't seen him for a long time?", Spike asks, feeling slightly intrigued about Derek.
Twilight brings Spike into a hug again and nods.
"Yeah. He just up and left without saying goodbye." Twilight starts silently crying again, really missing Derek. When Spike feels Twilight's tears drip onto him and hears her sniffling, he becomes a little angry and determined. He hates seeing Twilight upset and will willingly do anything to make her feel ten times a whole lot better. He wipes Twilight's tears away.
"Would you feel better if he came back?", Spike asks Twilight. She gives a small nod and says, "Yeah, but he has his own life now and it's his choice if he wants to come back or not."
Spike gives a sad frown, having thought for sure that Twilight would have agreed.
"Okay, Twilight," Spike simply said, making the wise decision to just end the discussion then and there.
Twilight sniffles and lets go of Spike, putting on a fake smile.
"Well, I better get back to these books. They can't organize themselves," she says, turning around and going back to the books. Suddenly, Spike gets an idea.
"Okay, Twilight. I'll just... go out and... get some fresh air," Spike says nonchalantly. He immediately walks outside, determination filled in his heart.
"Don't you worry, Twilight! I shall go to the ends of the Earth to find Derek and get him to come back, just to make you happy again!" On the last part, Spike lifts his head up to the skies and his voice echoes. He is going to do anything it takes to find Twilight's long-lost assistant bring him back to her, even if it means getting lost or going missing for many long days. Despite the fact that he himself is her second best assistant, Spike would do whatever it takes to cheer up Twilight by bringing back with him her original assistant and adoptive son: Derek.