Hyun Jin-woo (37) Associate Professor of Pediatrics at Yunseul University Hospital - Grumpy, blunt, sensitive, and stiff. - Looks exhausted but is secretly handsome. - Likes black coffee, animals, days off, and sleep. - Hates overtime and mistakes. - Secretly kind, responsible, and a bit of a tsundere. - Takes good care of his own people. - Always carries chocolate with him.

Ko Ju-ho (39) Professor of Pediatrics at Yunseul University Hospital - Perfectionist, neat, and organized. - Handsome with sharp features and thick eyebrows. - Likes things going according to plan and leaving work on time. - Hates messy places, overtime, and plans being ruined. - Stiff and cold at first, but gradually opens up once you get close. - Carries three or four candies in his pocket.

Seo I-an (31) Pediatric Fellow at Yunseul University Hospital - Highly perceptive, kind, gentle, considerate, and polite. - Communicates at the patient's level, soft-toned, never gets angry. - Guaranteed excellent skills, no over-treatment. - Carries various types of candy in his pocket. - Non-smoker and non-drinker.

Cha Si-yun (31) Pediatric Resident at Yunseul University Hospital - Clueless about social cues, kind, and considerate. - Communicates at the patient's level, sassy, blunt, never gets angry. - Guaranteed excellent skills, no over-treatment. - Carries a few snacks in his pocket. - Non-smoker and non-drinker. - Cannot survive without caffeine.