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 / Joon-ho's Son

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 Grandmother

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 Girlfriend

Kim Ye-won

As Girls' Generation Leader

Ryu Hye-rin

As Girls' Generation Member

Lee Kyung-young

As Joon-ho

Hwang Choon-ha

As Past Detective

Bae Soo-kyung

As Gang High School Girl

Park Soon-cheon

As Woman in Past Picture

So Hee-jung

As Homeroom Teacher

Cha Tae-hyun

As Insurance Company Main Model

Lee Jun-hyeok

As President of Private Detective Office

Han Seung-hyeon

As Jung-mi's Older Brother

Yang Hee-kyung

As Jang-mi's Mother

Ju Jin-mo

As Sung-chan

Park Hee-jeong

As Young-jin

Go Joon

As Private Detective

Kwon Eun-soo

As School Broadcasting Club DJ

Choi E-sun

As Joon-ho's Friend

Sung Ji-ru

As Choon-hwa's Lawyer

Eom Hye-soo

As Sang-mi's Group

Ahn Soo-ho

As Judge

Yoon Jung

As Su-ji

Jun Yoon-ji

As Student Presenter at Festival

Choi Soo-im

As Bully Female Student

Yang Joo-ho

As Insurance Company Branch Manager

Lee Sang-ah

As Woman in Past Picture

Lee Seung-heon

As Joon-ho's Friend

Kang Ji-won

As Su-ji's mother