Sister’s Diary (2020)

Gaeun and Suho grew up like siblings. However, Suho, who has loved Gaeun since he was a child, doesn’t express himself. One day, Suho accidentally sees Gaeun’s diary and finds out that Gaeun also likes her.

Suho goes to Gaeun and reveals her heart. Gaeun is not a sibling, but she refuses to protect her as she considers her parents who have raised her up to now.