I started it as a filler drama as I was waiting for another drama. I was in for a surprise as it was good quality drama which kept me hooked to the point it stopped being filler and I started anticipating its episodes.

I liked the quality storytelling, and the twists and turns. The action scenes were good But....

Sadly, these types of dramas have the main mystery to be solved by solving sub-quests, I mean, sub mysteries were simply not my thing. The bit-by-bit unravelling to the main mystery was not as rewarding as the wait nor was I interested in some student's death or side character's conflict with parent. All I wanted I was the mystery to be solved unfortunately I lost my patience.

I regret dropping it but never mind.

PS. How quick would be to accept the fact that the person you love is now in the guise of the person you hate.