Lawyer Lin Wan and Gu Shen, who comes from a construction site background, maintain a secret relationship that "ends when dawn breaks." She helps vulnerable groups protect their rights, while he silently guards her. When a rape case drags them both into a wealthy family conspiracy, Gu Shen's true identity surfaces—he is the youngest son of the Gu family who was "drowned" after being framed by his elder brother. Faced with pressure from the powerful, media encirclement, and the fog of an old case, they serve as each other's armor, using the law as a sword to uncover the dust-laden truth. Two people who once walked alone in the long night ultimately illuminate each other, welcoming their own clear sky.