I LOVE everything about this drama, it's the first (K/C/T/J) drama I've re-watched and will rewatch many more times without getting sick of it. It still blows my mind when I think about the plot of this drama, especially from Kang Chul's perspective, how this random woman (Yeon Joo) came to his world only to litterally be the "key to his life" in every way.

This is my favourite Kdrama and my favourite cross dimension drama. It is also the only cross dimension drama I've seen where there aren't any plot holes and where the main characters travel back and forth between the two dimensions several times. All the episodes are VERY detailed, relevant and much more fast paced than I remember it being. There are a total of 16 episodes in this drama, and it was the PERFECT length for this drama to develop and conclude with a satisfying ending.

The main leads, Lee Jong Suk and Han Hyo Joo had amazing chemistry and visuals, they looked so good together. I loved how all the side characters were relevant to the plot. They may not be relevant throughout the drama, but they had their roles to play, and when they came in, they became a major part of the plot, especially the villains. The OST fit really well with the romamce/thriller of the drama. I loved all of the cast, they were perfect for all their roles. Main leads aside, Kim Eui Sung was amazing as Oh Sung Moo who had some of the best plot twists and most unexpected character developments.

This drama has everything and will fit several genres including: romance, mystery, thriller, fantasy, sci-fi, action, psychological, medical and comedy. It's such a well rounded drama that I HIGHLY recommend to everyone.