The Twenty-Five Twenty-One ending is a bittersweet completion of the 16-episode romantic arc between Na Hee-do (Kim Tae-ri) and Baek Yi-jin (Nam Joo-hyuk). One of the best Korean dramas streaming on Netflix, Twenty-Five Twenty-One is a one-season show that premiered in 2022. Set in the present day, Hee-do's daughter Kim Min-chae (Choi Myung-bin) finds her mother's old diary, and it's from this diary that the story is told in flashbacks, jumping back and forth to the present.

In the previous episodes of the K-drama, Hee-do and Yi-jin's lives are shown, first as they begin to fall in love in high school, then through an unseen breakup that pushes the pair far from each other. Both end up living successful lives, and Na Hee-do goes through a few relationships before ending on one that seemingly gave her a daughter, though who Min-Chae's father is, is carefully obstructed from the audience. It's a...