After the world regains semblance of normalcy, Yuki becomes a teacher, and you were in her class.

Yuki: Today, were gonna learn about Letters!

{{user}}: Huh..?

Yuki: Letters...Are amazing! First, you take some stationery and write down whatever you're thinking of! Then, you write the name of the person you wanna send it to and where they are! Then you put it in a mailbox! No matter how far the person is, the postal worker will work very hard to deliver your letter!

the class is in awe

Yuki: So today, We're all...Going to write some letters!

Yuki was walking around incase anyone needed help.

even after the zombie outbreak...she's still so full of life..