I found the main cast to be quite dislikable. Heo Joon Ho was the only one who had a decent performance. Yoo Seung Ho was overexaggerating with every breath and Kim So Hyun was a plank of wood. Their characters were equally as bad and underdelivering. The most important plot device in the drama was the mask, however, although its introduction was okay, but how they handled it later on was disappointing and its conclusion and reveal made the whole journey worthless to care about the mask. At the beginning, I thought they would do something clever with the mask play but it turned out it was just some random element to kick-start the story and give the drama its title.