A young couple's love is tested when Sun-jin is diagnosed with a rare form of Alzheimer's disease.

Jung Woo-sung
as Choi Chul-soo

Son Ye-jin
as Kim Su-jin

Baek Jong-hak
as Seo Yeong-min

Lee Sun-jin
as Jung An-na

Park Sang-gyu
as Mr. Kim

Kim Hee-ryung
as Mother

Seon Ji-hyun
as Jeong-eun

Kim Bu-seon
as Madame Oh

Jang In-han
as Supervisor

Kwon Byung-gil
as Doctor Lee