It is about a modern-day plastic surgeon, who is kidnapped and brought back in time to the Goryeo period, 700 years in the past, where she falls in love with her kidnapper, a warrior who is the leader of the royal guard.

Choi Young travels to the future and brings back Yoo Eun-soo (Kim Hee-sun), a modern-day doctor from Seoul, to save the queen's life.

He promises that he will return her to her world once she saves the queen, but the royal advisor schemes and persuades King Gongmin to force Eun-soo to stay as she can be useful to him.

The series follows how Choi Young and Eun-soo evade and overcome impending problems and whether or not they succeed in getting her to heaven's door in time before it closes for good.

On October 19, a little before the end, the news was published that Lee Phillip (who played Dr. Jang Bin), sustained an eye injury and had to pull out of the drama.

[21] The writer Song Ji-na uploaded the original script on her website and it was obvious that there were considerable changes in the final product, some of them because of lack of money.

Drama producer and direction Kim Jong-hak, whose credits include Eyes of Dawn, Sandglass, Daemang (2002) and Legend (2007), was accused of double-contracting the Faith OST rights (to two separate companies) in the fall of 2012 became the subject of a police investigation for embezzlement and breach of trust.

[22][23][24] This tragic death and many of the "ills" of Korean dramas have been attributed to the outsourcing of production to independent companies which struggle to cover the exorbitant cost of writers and stars.