Episode 1 S01 E01

Lee Dong-wook (as Park Ri-hwan) Jung Ryeo-won (as Kim Haeng-ah) Lee Jong-hyuk (as Kang Suk-joon) Park Hee-von (as Lee Seul) Park Cheol-min (as Kim Joon-hyuk) Bae Jong-ok (as Park Sun-young) Kim Jung-nan (as Oh Se-young) Park Joon-geum (as Yi-seul's mother) Lee Seung-joon (as Kwon Ji-hoon) Park Won-sang (as Jo Dong-il) An Woo-yeon (as Ye Joon-soo) Kim Sa-Kwon (as Hong Jung-woo) Kim Ri-na (as No Tae-Hee) Han Seo-jin (as Kim Haeng-A (7 years old)) Go Bo-gyeol (as No Dong-Hwa) Seo Jeong-yeon (as Aunt Gong Joo) Yoon Chan-young (as Park Ri-Hwan (15 years old))

friendship childhood friends slow burn romance