Surgeon Bong Dal-hee

Bong Dal-hee (Lee Yo-won) approaches her life and work with a simple-minded gungho sincerity. She's had frail health since she was a little girl, and after she undergoes heart surgery, Dal-hee decides to pursue her dream of becoming a doctor. She graduates from a little-known medical school in her hometown, the remote island of Ulleungdo, and against all odds, gets accepted into the prestigious Hankook University Hospital residency program in Seoul. Dal-hee is determined to become a cardiothoracic surgeon, all the more so because of her own heart condition. Her old-fashioned name, provincial upbringing and lack of competitiveness mark her as different among the first year residents. She immediately gets on the bad side of Ahn Joong-geun (Lee Beom-soo), a brilliant but extremely strict cardiothoracic surgeon who often gets angry at the mistake-prone Dal-hee. Adding to the negative impression is Dal-hee's friendship with recently divorced general surgeon Lee Geon-wook (Kim Min-jun), who was Joong-geun's rival since their intern years. Geon-wook is attracted to Dal-hee, but he still has lingering feelings for his ex-wife, pediatrician Jo Moon-kyung (Oh Yoon-ah). Geon-wook and Moon-kyung split up after he learned that their six-year-old son was fathered by another man before they married, leaving him feeling betrayed and angry. Meanwhile, as they continue to work together, Joong-geun and Dal-hee grow closer. Called a "troublemaker" by her colleagues but loved by her patients for her compassionate personality, Dal-hee must learn to deal with professional setbacks, tensions on the job, hospital politics, patient deaths, romantic confusion and recurring ill health, on her way to becoming a full-fledged surgeon.