Meet the characters:

Kim Seokjin as himself/oppanim

ChoKyuhyun as Kim Kyuhyun (Seokjin's elder brother)

Min Yoongi as himself (Seokjin's colleague and one of the friends)

Kim Namjoon as himself (Seokjin's cousin)

Jeon Jungkook as Officer Jeon (A police officer and Seokjin's best friend)

Kim So Eun as Choi Solbi (Jin's girlfriend who died in an accident and Jiwon's sister and best friend) (cameo)

And Reader (you) as Choi Jiwon/ Kim Jiwon.

And Dr Park (Julia) is a fictional character in this story.