To my regret, in my opinion, some points were not right with this show. The story is quite promising, but after only a few episodes it is clear that the script itself does not know where it wants to go. The story lacks the necessary stringency to consistently honour the great drama of the events.
Supposedly, a crucial event could not be corrected, and no one questioned this statement. Well, that is the internal logic in the story - but after the younger self of Ban Ha-Ni knows the future and understands why the older Ban Ha-Ni had mourned and sunk into depression for 20 years, and she is back in the past to live her life again, nothing changes about the future in the end. The young Ban Ha-Ni's new experiences, knowledge and insights have apparently not changed anything about the old Ban Ha-Ni's personality! Impossible! I think with an initial story like that, you can't focus on one detail and not pay attention to everything else.
As for the choice of actors, unfortunately the chemistry between the couples was not right. In my opinion they are not a good match. Sometimes I thought the actress of a supporting role was a better match for the lead actor. Also I really wanted to witness that, like in the well-known fairy tale, the ugly duckling becomes a beautiful swan in the end. Unfortunately, that did not happen.