Let me review this drama by points,

1) Amazing plot ruined by story writer

2) Chemistry between the two main leads not enough. First I think it will grow over the upcoming episodes but I am wrong.

3)Mika's brother relationship with Mika's friend is more interesting than the two main leads.

4) Lead actress performed well than the lead actor

5) If they use this clock concept with perfectly well written story ,this drama will be the best drama of the year.

6) Overall it still watchable if you have time , just give it a try for the handwork of about time drama cast.