The Bright Fire Light centers around twins, Tianwan and Wantagon (Chompoo Araya). Wan returns to Thailand from abroad after receiving news of her father's abrupt death. Though it's said that he died of a car accident, Wan knows her father better than that and suspects foul play. She later discovers that her father had two business partners that betrayed him, Khun Anon and Tian's boyfriend's father. Because of this, Wan seeks revenge against them to get justice for her father's death.