On Your Wedding Day is a South Korean romantic film that tells the story of a man named Woo Yeon who has been in love with his high school classmate Seung Hee for over a decade. Despite his feelings, Seung Hee has always seen Woo Yeon as just a friend. As they both grow older, their paths diverge and they lose touch.
Years later, Woo Yeon is invited to Seung Hee's wedding. As he attends the ceremony, he reminisces about their past and the moments they shared together. He realizes that he still has feelings for her and decides to make one last attempt to win her heart.
The film explores themes of unrequited love, friendship, and the passage of time. It captures the bittersweet emotions of longing for someone who may never feel the same way. Will Woo Yeon finally be able to confess his true feelings to Seung Hee on her wedding day?