Cha Yu Ri, a ghost for five years, realizes her daughter can see her. Just as she decides it's time to move on, she is returned to her human form.

Kim Tae Hyun is a promising young surgeon, but his finances take a dive when his sister's health condition requires costly dialysis treatments. When Tae Hyun subsequently falls into a vicious cycle of debt, he assumes the alias of "Yong Pal" and begins making house calls for criminals who are willing to pay top dollar. Complicating things further, Tae Hyun gets involved with Han Yeo Jin, a comatose patient at the hospital.

Hyunjun and Sawoo, close friends and rivals from the South Korean special forces, are recruited by the secret agency NSS. They both fall for Seunghee, the beautiful but lethal profiling specialist at NSS. When they are faced against each other in a nuclear terrorist attack, they are forced to make their final decision and Seunghee's formidable secret is revealed.