This show started off strong with some great character things and romantic development. It made math fun for a bit! Unfortunately, this show suffers from "should've only had 12 episode"-itis and it showed. Once it hit 12 episodes, everything was nonsense. The murder plot was not only ridiculous and needless, IT WAS ALSO RESOLVED POORLY without any of the emotional impact it could've had. Was this only added to pad the episode count? What was the POINT? The last-minute unearned redemption -- NOT character development as others will say -- of several characters who have never shown remorse until the last episode was salt in the wound. The teens were awesome. Haengseon and Chiyeol, when not bogged down by that ridiculous murder plot, were amazing. Haeyi and Haengseon are really the heart of this show. Too bad it failed them.