First and foremost, I must say that I am a romance drama fan so I was quite hesitated to watch this drama. And also I didn't know any of the casts to prompt me to watch it. I didn't quite remember why I watched this drama seriously..... But I never regret it:) For the story... 1.) Amazing story line that hooks me up every episode. I literally lost sleep over this drama cause I was so so so curious about the story and those cliffhangers definitely left me crazy. The idea of the time-mismatching walkie-talkie is really interesting and is well used in this drama, although I hoped for a more detailed backstory of the walkie talkie to make it more completed. 2.) I also had some moments where I lost the story and couldn't follow the logic, then I rewind back so that I can get back on track. It happens for me so often but kinda feel that my IQ is increased after the drama hahaha... 3.) The ending was left half-open but definitely did not leave us hanging (maybe a teeny weeny bit). Probably for a sequel which I think is highly possible due to the nature of this drama. A pre-sequel is also possible to talk about the detailed backstory of characters as well as the walkie-talkie. Looking forward to it:) For the cast/acting... Casts is so goooood. Like I said earlier, I didn't know any of them when I started watching it but they totally impressed me so much. Totally. I was also very impressed by the acting of the minor characters and the sub story leads. For the music... I don't know the title to the opening track but it's really suitable for the drama, feels like the characters are walking back in time. Generally enjoyed the music as it was able to build up the intense at every climax. Definitely a re-watchable drama or SEASON 2 pls. Binge watch it or lose your sleep haha..