Bo Young moves into the mansion of the previously wealthy grandmother, Wang, as a caregiver with a dangerous intention. Mother Kim, the only blood relative of Wang who hired Bo Young, sets conditions such as 'Do not bring anyone, especially children,' and 'Do not go near the reservoir'. Ominous and bizarre signs continue in grandmother Wang's huge mansion located next to a reservoir called 'Gwimot', where people are dying, and Bo Young finds out that foreigners who have visited the place have suffered a mysterious death...

Lee Young Kook is a widower with three children. He still hasn’t gotten over the death of his wife. He decides to hire Park Dan Dan as a live-in tutor for his kids and he becomes attracted to her. Meanwhile, Park Dan Dan has bright and positive personality despite her harsh situation.

Wie Dae-Han (Song Seung-Heon) is an ex-lawmaker and is a materialistic kind of politician. He wants to get elected as lawmaker again. One day, 18-year-old girl Da-Jung (Roh Jeong-Eui) comes to him. She tells him that he is her real father. Her mother raised four children, including Da-Jung, alone, but she died in a hit-and-run accident. Da-Jung is the only one now taking care of her 3 younger siblings. Wie Dae-Han accepts Da-Jung and her 3 younger siblings. He carries out “The Great Show” to become a lawmaker again.

The essence of love is fading and is evermore harder to do. In this day and age, will there be love that is woeful and forlorn just for the sake of love itself? Love in Sadness is a love story that encapsulates the mythical-like fate of love that is so coveted that it ignores all bounds. In it, love outweighs what the world thinks, ignores the pain and anguish with it, and pursues its destiny. In the drama, Ma Ri is a beautiful girl, married into wealth with a seemingly perfect life. Ironically, her husband, In Wook, who looks like a more than ideal husband, is an obsessive lunatic who is also violently abusive. When he pushes her too far, she reaches out for help from Jung Won, an honest, smart, handsome plastic surgeon. And when he agrees to help her escape from her husband's hands, they fall in love. But In Wook, who is consumed by his obsession for her, isn't going to let her get away from his grasp. Watch as these two characters struggle to stay on their arduous road to love.