Kim Ha-neul as Yoon So-eun

Yoo Ji-tae as Ji-in

Ha Ji-won as Soe Hyeon-ji

Park Yong-woo as Ji Dong-hee

Shin Cheol-jin as Security Guard

Yoo Tae-gyun as Yoon So-eun's Father

Lee In-ok as Yoon So-eun's Mother

Lee Yeong-gwang as Professor

Kim Sang-won as Ji-in's Friend

Kim Do-yoon as Ham Radio Club 1

Lee Kyung-Hoon as Literature Club 3

Kim Min-joo as Hur Sun-mi

Maeng Bong-hak as Doctor

Kim Bang-Sun as Librarian

Kim Do-sik as Butler