"Giant" covers the lives of the three siblings growing up in the 1970's and their pursuit for revenge; Lee Kang-Mo (Lee Beom-Su) is a man who carries deep sorrow, his younger sister Lee Mi-Joo (Hwang Jeong-Eum) & his older brother Lee Sung-Mo (Park Sang-Min). Lee Kang-Mo's father died due to a friend of his father. Because of this, Kang-mo also lost his mother and had to separate from his younger sister and older brother. Kang-Mo was then raised by a man named Hwang Tae-Seob (Lee Deok-Hwa). Kang-Mo also falls in love with Hwang Tae-Seob's daughter Hwang Jung-Yeon (Park Jin-Hie). By a cruel twist of fate, it turns out Hwang Tae-Seob turns out to be the man responsible for Kang-Mo's father's death. Now Lee Kang-Mo & Hwang Jung-Yeon's relationship changes as Lee Kang-Mo becomes driven for revenge..