From the title happiness, I feel that it is titled like that because it is the happiness of a person that guides the infected so that they become more conscious and they are more resistant to the thirst for blood. From the character and performance of the performers, this is a fantastic narrative. This 2021 kdrama comes highly recommended. I was a little disappointed with the finale since it felt like the drama was ending in the last minute, but it was lovely. It's fantastic.