Sunny

Yoo Ho-jeong

Na-mi

Shim Eun-kyung

Young Na-mi

Jin Hee-kyung

Choon-hwa

Kang So-ra

Young Choon-hwa

Koh Soo-hee

Jang-mi

Kim Min-young

Young Jang-mi

Hong Jin-hee

Jin-hee

Park Jin-joo

Young Jin-hee

Lee Yeon-kyung

Geum-ok

Nam Bo-ra

Young Geum-ok

Kim Sun-kyung

Bok-hee

Kim Bo-mi

Young Bok-hee

Min Hyo-rin

Young Su-ji

Kim Shi-hoo

Young Joon-ho / Joon-ho's Son

Park Young-seo

Young Jong-ki

Chun Woo-hee

Sang-mi

Kim Hye-ok

Na-mi's Mother

Jeong Seok-yong

Jong-ki

Ha Seung-lee

Ye-bin

Kim Young-ok

Na-mi's Grandmother

Baek Jong-hak

Nami's Husband

Jung Won-joong

Na-mi's Father

Kim Won-hae

Teacher

Kim Sae-byuk

Class Monitor

Kang Rae-yeon

Jong-ki's Girlfriend

Kim Ye-won

Girls' Generation Leader

Ryu Hye-rin

Girls' Generation Member

Lee Kyung-young

Joon-ho

Hwang Choon-ha

Past Detective

Bae Soo-kyung

Gang High School Girl

Park Soon-cheon

Woman in Past Picture

So Hee-jung

Homeroom Teacher

Cha Tae-hyun

Insurance Company Main Model (cameo) (non-crédité)

Lee Jun-hyeok

President of Private Detective Office

Han Seung-hyeon

Jung-mi's Older Brother

Yang Hee-kyung

Jang-mi's Mother

Ju Jin-mo

Sung-chan

Park Hee-jeong

Young-jin

Go Joon

Private Detective

Kwon Eun-soo

School Broadcasting Club DJ

Choi Yi-Sun

Joon-ho's Friend

Sung Ji-ru

Choon-hwa's Lawyer

Uhm Hye-soo

Sang-mi's Group

Ahn Soo-ho

Judge

Yoon Jung

Su-Ji

Jun Yoon-ji

student presenter at festival

Choi Soo-im

bully female student

Yang Joo-ho

insurance company branch manager

Lee Sang-ah

past picture

Lee Seung-heon

Joon-ho's friend