This is a side-story to a scene that happens during the first volume. It is just after Sebastian saved Ciel from that guy (can't really remember his name…) and Ciel is being carried by Sebastian back to the Phantomhive estate. I do not own any of the Black Butler characters.
Sebastian sighed. "Really, young master, what am I going to do with you?"
Sebastian was walking down the dirt road with his young master in his arms, as if Ciel were a princess being carried by her prince.
Ciel just pouted. "It wasn't my fault!" he screeched. "You should have been paying less attention to the care of the estate, and more on me!"
Sebastian looked at Ciel. Ciel had then realized what he had said. He couldn't really tell if he meant it that way or if it was just a simple slip of the tongue.
"I mean, it's the housekeepers' jobs to keep the house in orderly condition, isn't it?" Ciel quickly tried to cover but failed due to his blushing.
Sebastian smiled. He was pleased to finally know what had been bothering his young master. For the past week, Ciel had been eyeing Sebastian oddly. Even now, Ciel just looked at Sebastian.
"Young master?" Sebastian asked finally after about a minute.
Ciel quickly looked away. He couldn't help but look at the perfect demon, it was as if he was sculpted by the gods (but y'know then sent to hell…).
"Is there something wrong, young master?" Sebastian asked again.
Ciel still didn't speak. He almost refused to talk to Sebastian. Almost.
"Oh young master, I thought I should let you know that Miss. Elizabeth is coming over and she said that she would bring many costumes for you to try on."
"What?" Ciel exclaimed.
"Ah ha. So you can speak," Sebastian said, smiling a devilish smile.
"Why you little-"
"Please young master, a noble shouldn't swear."
Ciel's face turned from shocked to pissed, with his blush getting to a deeper shade of red.
"Young master, please talk to me. It's my job to take care of you and in order to so that, I need to know what is wrong with you," Sebastian exclaimed.
Ciel still looked away.
"Young master, is it about me? Have I done something not to your liking?" Sebastian asked.
Ciel still didn't look at Sebastian."It's not that, it's exactly the opposite. It's like you're too perfect. I wish you'd just notice it already," Ciel thought. "I want you to be mine and only mine."
"Young master?" Sebastian asked a third time, this time taking different approach to the situation.
When Ciel turned around, his nose and Sebastian's nose were almost touching. Ciel almost fell from Sebastian's arms, out of shock.
"W-what are y-you d-d-doing?" Ciel stuttered.
"Trying to find out what is wrong," Sebastian answered simply.
Ciel couldn't speak. He didn't know what to say. Well, before he could actually get anything out, they had arrived at the estate. May-rin, Baldroy, and Finnian all huddled around the young master, asking him if he was alright.
"I'm fine," Ciel said, what seemed like 20 times over.
After they all had finally left him alone, Sebastian knelt down on one knee and apologized to the young master for not having dinner ready. Ciel simply dismissed the words and went to his bedroom. When Sebastian had finished dressing him down for bed, the young master had a strange request for the demon.
"Sebastian," Ciel whispered, "stay here until I fall asleep."
Sebastian gently smiled. "Of course, young master."
As Sebastian watched over his small master, he noticed that he started to talk in his sleep.
Sebastian leaned in closer, as if his were going to receive an order from his young master.
"Be mine…." Ciel whispered. "Be mine and only mine…."
This took Sebastian by surprise, thought you could never tell it. He stood perfectly still and instead, offered a slight smile. As he left his young master's chambers, he whispered "So that's my young master's true face?" and released a small laugh. He then began to prepare for tomorrow.