Summary by Sorasan.

JINNO-SENSEI FLASHBACK: "Yukihira-sensei...'that' is a student of your class."

Yukihira totally doesn't know what to do first...

It is explained that this was when Yukihira was 22 years old and Yuka was 10 years old. He calls out to her to get her down, but she refuses, insulting him along the way. Yukihira gets angry (and puts on a ogre mask). Mikan and the others can't believe that it is him speaking... Noda-sensei says that in his youth, Yukihira was quite a rough young man...

Yukihira grabs the latter Yuka is on.

Meanwhile, The high school principal gets a call from a furious Jinno-sensei due to Yukihira's "immature" behavior around the students at the assembly. This causes Jinno-sensei to zap him with his lightning.

Among the principals is someone that Mikan has not seen before...It is the elementary school principal all grown up! (And boy is he ugly...) Of course, Mikan has questions for why he appears all grown up. Noda-sensei tells her that Yuka stopped his time.

Onto another part...

Yukihira arrives at his classroom, where he is welcomed cheerfully by everyone except Yuka. (She's looking at him with evil aura around her.)

Later, Yukihira is speaking with another teacher about Yuka. It ends up as flirting, and the younger students catch him. They are there to tell him that Yuka has run away again.

He goes out and yells for her. He finds her falling from the top of the latter (probably zapped from the top of the wall). He catches her before she hits the ground. He asks her if she's okay, but when she opens her eyes and sees him right in her face, she punches him and runs away. Of course, he isn't going to take that. He throws a pig head at her and grabs her by the shirt. He asks her why she does what she does and thinks if it's fun for her.

Yuka starts crying and says that she's the only one in the class that doesn't receive letters. So she had the idea to go outside of the school to go search for her family...

Yukihira calms down as he notices how beat up she is from the zap. She faints and he catches and holds her.