This series got off to a good start, but took a wrong turn around ep 10 and largely fell apart. The plot centers around Dr. Tin, who gets trapped in a time loop that he can only escape by saving Tol, an accident victim. He repeatedly fails, falls asleep, then begins the same day again, etc. Along the way he gradually uncovers more and more of the mystery of what happened, and draws closer and closer to Tol, the man he has to save.

It's quite well written - until it's not. Close to the end the perspective shifts to Tol, which deflates all the dramatic tension built up to this point, and then suddenly people's personalities change, to the point it doesn't feel like we're dealing with the same characters anymore. The story also starts to take a lot of "cheats", where the "rules" of the setup are changed in fairly silly ways - like all of a sudden kisses restore memories of past time loops - even if non-consensual, even unwanted, so it's not Love or something, it's just lips touching that works. There's also a magical notebook which makes no sense, i.e. if you go back in time, what you wrote before shouldn't be there anymore, and the way it's given to someone else makes no sense.

The finale is so random that I stopped caring what happened, and the ending is flat and anticlimactic. It's happy-ish although it doesn't make sense so it's not really satisfying.

The acting is superb all-around. This is Tee's best performance - he was adorable in Miracle of Teddy Bear, but here he plays are darker and more complex character, and everything he does is so authentic. Tae is also wonderful in this - he has that impish smirk, but he can also play cute and vulnerable and then shift to on-fire sexy - but it's his subtle moments that are the most impressive. At the end of Ep 9 he's so powerful - both of them are. Their chemistry is so on point, and so natural, and their characters are so fully realized. But then that's all thrown out and they essentially become different people.

The music is way better than typical - there are no old-fashioned power-ballads, and the soundtrack effectively supports the story.

One warning - there is a huge amount of secondhand embarassment in this - Tin is a terrible liar and he screws everything up constantly, and it's painful to watch. It's very well done, but I had to take breaks sometimes.

I loved this series up to about Ep 10 - after that I more or less stopped caring. It was still overall a good experience, but the lazy writing in the last few episodes prevented this from being one of my favorites of all time, and I was sure it would be.