You should only watch this if you can make sure you won’t be too emotionally invested in this because once you are in there is no out. I never thought the drama would turn out to be so good. The turning point is really at EP 8 that is the point you really can’t pull yourself out anymore. I feel so much empathy for Zio Guruem Lee Son and Yoona like seriously a happy ending for them is all I hope for now. They all deserve to live a good life. Even though Lee Son and Yoona are the bad guys in this drama, they are still the victims of the whole lab experiment thing. I never thought that an action thriller drama can make me laugh and cry. Normally I only feel tension. I think the main cast did a great job acting, the chemistry is off the chart! The OSTs was absolutely amazing, there wasn’t a drama where I liked all the OSTs before. Overall this is a must watch drama if you are looking for an emotional rollercoaster and action scenes