Prologue:
Sora was still in a daze about the past few days' events. It seemed like ages ago that he had started the Mark of Mastery exam with Riku. But he had failed… He had ended up relying on Riku to save him resulting in Riku becoming a fully fledged Keyblade Master while Sora had been left to train for another year before he could take the exam again. As if these events couldn't shock him enough, Riku had brought Kairi to the Mysterious Tower so Yen Sid could teach her to become a Keyblade Master as well.
"At least I get to train with Kairi this time," Sora thought, trying to be optimistic.
"Of course you would enjoy training with Kairi." Sora jumped. The voice had from his head and sounded faintly like someone he recognised.
"Roxas?" Sora asked aloud. "Is that you? How is it I can hear you? And what do you mean of course I'd enjoy training with Kairi?"
"Whoa whoa whoa one at a time now," replied Roxas. "To answer the first question, yes it's your dear nobody, Roxas. Second of all…well…I don't know. And thirdly, you know exactly what I mean. Just because I'm not there in person don't think I don't know you like her. I am in your heart after all."
Sora couldn't argue with that logic.
"Aha silence," shouted Roxas in triumph. "Well, when are you going to admit it to her?"
Sora started blushing.
"Well I was going to admit it when she found me again at The Castle that Never Was but…"
"Well? But?"
"But Ansem…or Riku was there."
"Hmph excuses excuses," teased Roxas.
"Does you being able to hear my thoughts have something to do with me getting captured by Xehanort and the new Organisation XIII?" asked Sora, rapidly changing the subject.
"Like I said…I don't know but there's no need for you to continually talk aloud to me, I'm inside you not outside," answered Roxas. Sora hadn't realised he was speaking aloud. He shrugged casually and returned to sitting silently on the stairs to Mysterious Tower for another several minutes.
"Why are you so gloomy?" asked Roxas.
Remembering to only think the words this time, Sora thought: "Well…I've been on so many adventures and done so many things yet apparently I'm still not good enough to be a Keyblade Master."
"How could you say that even when you know the test was messed with by Young Xehanort?" exclaimed Roxas. "You know that you would have passed had the test gone according to plan! Besides, you seemed so happy when Riku became a Keyblade Master and Kairi came here to train."
"But after being captured by Xehanort how do I know that there is not too much darkness is in me," cried Sora mentally. "How do I know that their lives aren't being put on the line just being around me? What if I'm too weak to hold it all back?"
"I'm sure Riku and Kairi would never let you fall into darkness," reassured Roxas.
"Thanks," replied Sora.
"And besides…just look at Riku, he fell into darkness and he's turned out just fine!" exclaimed Roxas. "Anyway, enough being gloomy because if you want to pass the Mark of Mastery exam you're going to have to train."
"Yeah, I guess you're right."
As if on cue Kairi walked out of the tower and sat down on the steps next to Sora. Despite himself Sora found a few of his worries melting away. Roxas chuckled to himself inside Sora.
"So…do you want to train with me?" Kairi asked.
"Sure," replied Sora, a grin forming on his face.
"Know any good worlds?"
"I could name a couple," said Sora, the grin now fully implemented on his face.
"Well let's go then."
"Hang on a sec I'll just go get a star shard from Master Yen Sid to travel with."
Sora ran up the tower to get a star shard while Kairi waited at the foot of the stairs. When he got back he asked Kairi if there was anywhere she would like to go in particular.
"Not really," she replied.
"I think I know somewhere you'll like," smiled Sora.
"Really?" asked Kairi. She held his arm as Sora held out the star shard in his other hand and activated it. Some way up the tower at a lone window, Riku watched as they bounced away into the sky in a ball of blue light.