Tiffany Hwang, a workaholic woman who is searching for someone whom she can be her lifetime partner until she found an dating advertisement so she went to the dating agency which TaeYeon was the one who managed alongside with her apprentice SooYoung, they will find her a person that fits her criteria but what if Tiffany will fell in love with TaeYeon instead of finding her a partner?

The present Kim TaeYeon wish to save her first love from death until she met her future lover way back from the past.  

Kim Taeyeon and Jessica were happily married for almost 3 years and they were blessed by a handsome son, Kyungsan but there was something odd on their relationship because Jessica acted as the husband and worked under their company while Taeyeon acted as the wife taking good care of their son and doing the house chores but they were still happy living that kind of life.

Jessica spend her whole life in the hospital ever since she's 7 years old because of severe leukemia that causes her stress and lack of sleep until one fateful night, the dream spirit visited her on her dreams and blooms into friendship. She's excited when the sunset came because it's the time when TaeYeon will visit her every night in her dreams again.