"So...... You guys are in last year of high school?", both of them nodded.
Jieun and the two young boys are seated in living room as she served them cold cola.
"And what kind of subject that Taeyong will teach you?", Jieun has to make sure that her best friend didn't teach these kids the wrong thing.
"Some basic subjects like math and language.", the brown haired boy which called Haechan answered.
"Well, he nailed math in high school though.", she murmured to herself.

Mark just sat quietly, observing as the girl and his friend talking. She said to Haechan that she's a university student, just like their Taeyong hyung. But isn't she looks too young to be one? And why is she in hyung's house? His girlfriend, perhaps? A lot of question going through his head, yet he keep quiet.

"Err.. Noona.... Are you Taeyong hyung's girlf......", Haechan stopped himself from asking as he heard the front door opened, following by Taeyong's voice that half-calling half-singing Jieun's name.
"Oh? You guys here already?", Taeyong looks at his juniors that sitting in the living room with Jieun.
"Welcome back, T.", Jieun smiled at him.
Taeyong walk to her side and cupped her small face with his hand, "I bought you cookie dough flavored ice cream, bae.",
"Big tube?",
"The biggest."
Jieun chuckled and snatch the plastic bags from Taeyong's hand.
"Now go teach the kids. I have a date with the ice cream", then she just walk to the dinning area.
"Yes, you're welcome, Jinjin bae.", he laugh softly then faced the two high school boys that just sat silently watching their interaction, "So....... Where should we start?".

As Taeyong explaining some math formulas to them, Mark keep glancing to the dinning area. He silently observing Jieun. He watched her wearing a headset as she choosing song from her phone. He watched her opening the ice cream tube's lid. He watched her smiling by herself as she took her first bite of ice cream, and somehow he smiled too. He feels a little bit attracted to her, he knows it. Is it because her small figure that doesn't looks like a people her age? Or is it because he want to know what's her relationship with Taeyong hyung? Because she definitely not his sister, and he act sweetly to her. Taeyong hyung is a real definition of ice prince in the dance school, he ignored all the girls, so this is the first time he and Haechan see him all smiley to a girl.
Later that night he found out that Jieun is just his hyung's best friend, just like the other three that also live in the house, and he don't know why he felt relieved.