Once they explain what is their theory of the time travel, things start to make more sense and you can enjoy the drama better.

Since the story allow it, it has a bunch of plot twists, which makes hard to predict what comes next or who is the person behind of all.

The amount of tension is on point. It's addictive. At the end of each episode I was anxious to watch the next.

The only point that bothered me it was when they tried to add romance on it. Due the main character past, it becomes quite weird to watch.

Overall, a good drama.