After the sixth episode this was easily on my favorites list not because the plot is relatively original or mind blowing, but it is very well done and something rarely seen in K-dramas. However, Lord of the Flies by William Golding and the japanese manga and anime Monster have done a great job with this concept. The reason this does not quite get a ten from me is that I'm a tough grader and while it does not have many flaws, it still has some. For one, thrilling moments in this plot are triggered by coincidences or fate. I feel like for such a well done and thrilling drama that seems a little ridiculous. Seven students of the top private school in Korea receive a letter that compels them to stay in school for the holidays. First of all, this school is known for its rigorous and strict rules and you're telling me seven students are going to stay in a school they consider a jail just because they received a letter... Yeah, okay. As a person who went to boarding school can I just attest that no threatening letter would have stopped me from going home. In the midst of the mysterious letter, an injured stranger appears around the school area seeking help. A person ends up dead and hence starts the mystery. Who has sent the letter and are the deaths connected to the letter? Dun Dun Dun *mysterious music* Nonetheless, the story is amazing though yes, a point was docked as towards the end, yet another mysterious person appears which honestly was slightly overdone. Furthermore, the fundamental question of this is never quite answered. It somewhat takes a cop out. The question being a nature and nurture type of question. Are monsters born that way or are they made? Well, that is ultimately left to your interpretation. There are moments where this drama feels tangled in it's own philosophy and doesn't quite know where to go. However, despite what seems like a negative review, the characters are absolutely great, the plot very well done and the directing is stellar. The acting is also fantastic and this drama engaged me to no end. I watched episode after episode with little pause. A strong recommendation.