| Jung Ryeo-won |
| Oh Yeon-seo |
Renowned for her supporting role in "My Lovely Samsoon" in 2005, Jung will take the lead role of Seo Ju-young, a cardiothoracic doctor, with a strong charisma and humanity.
"The character Jung will play is a perfectionist who overcomes difficult situations and finally becomes a top cardiothoracic surgeon. She has decided to take the role as she can learn many things from the character," her agency said.
Also, Oh Yeon-seo will join the drama in the role of Choi Ah-jin, the youngest cardiothoracic surgeon in the hospital.
Meanwhile, Kwon will play the role of Park Tae-shin, a lead character who is a specialist in cancer surgery.