Coworkers Nam Jung-gi and Ok Da-jung have contrasting nice and nasty temperaments. Will Jung-gi's goodness ignite Da-jung's anger or will he cool her fury?

Marketing Department Manager, Nam Jung-gi (Yoon Sang-hyun) is so nice that his colleagues call him "Father Theresa" and "Walking UNICEF". There is nothing that can ruffle Jung-gi's feathers but his coworker, Ok Da-jung (Lee Yo-won), who is so nasty tempered she's been nicknamed "Fire Da-jung", and isn't impressed with Jung-gi's affable nature. In fact, his goodness seems to bring out the worst in her, fanning the flames of her fury at everything and everyone. Will Ok Da-jung finally push Nam Jung-gi over the edge and ignite his anger, or will he eventually be the one to cool hers?