Sunny

Yoo Ho-jeong

as

Na-mi

Shim Eun-kyung

as

Young Na-mi

Jin Hee-kyung

as

Choon-hwa

Kang So-ra

as

Young Choon-hwa

Koh Soo-hee

as

Jang-mi

Kim Min-young

as

Young Jang-mi

Hong Jin-hee

as

Jin-hee

Park Jin-joo

as

Young Jin-hee

Lee Yeon-kyung

as

Geum-ok

Nam Bo-ra

as

Young Geum-ok

Kim Sun-kyung

as

Bok-hee

Kim Bo-mi

as

Young Bok-hee

Min Hyo-rin

as

Young Su-ji

Kim Si-hoo

as

Young Joon-ho ...

Park Young-seo

as

Young Jong-ki

Chun Woo-hee

as

Sang-mi

Kim Hye-ok

as

Na-mi's Mother

Jeong Seok-yong

as

Jong-ki

Ha Seung-lee

as

Ye-bin

Kim Yeong-ok

as

Na-mi's Grandm...

Baek Jong-hak

as

Nami's Husband

Jung Won-joong

as

Na-mi's Father

Kim Won-hae

as

Teacher

Kim Sae-byuk

as

Class Monitor

Kang Rae-yeon

as

Jong-ki's Girl...

Kim Ye-won

as

Girls' Generat...

Ryu Hye-rin

as

Girls' Generat...

Lee Kyung-young

as

Joon-ho

Hwang Choon-ha

as

Past Detective

Bae Soo-kyung

as

Gang High Scho...

Park Soon-cheon

as

Woman in Past ...

So Hee-jung

as

Homeroom Teach...

Cha Tae-hyun

as

Insurance Comp...

Lee Jun-hyeok

as

President of P...

Han Seung-hyeon

as

Jung-mi's Olde...

Yang Hee-kyung

as

Jang-mi's Moth...

Ju Jin-mo

as

Sung-chan

Park Hee-jeong

as

Young-jin

Go Joon

as

Private Detect...

Kwon Eun-soo

as

School Broadca...

Choi Yi-sun

as

Joon-ho's Frie...

Sung Ji-ru

as

Choon-hwa's La...

Eom Hye-soo

as

Sang-mi's Group

Ahn Soo-ho

as

Judge

Yoon Jung

as

Su-ji

Jun Yoon-ji

as

Student Presen...

Choi Soo-im

as

Bully Female S...

Yang Joo-ho

as

Insurance Comp...

Lee Sang-ah

as

Woman in Past ...

Lee Seung-heon

as

Joon-ho's Frie...

Kang Ji-won

as

Su-ji's mother