Sino ang May Sala?: Mea Culpa follows the lives of eleven law school graduates whose lives are forever changed after a celebratory trip to Baguio ends in a tragic vehicular accident. In a moment of panic and fear for their promising futures, they decide to cover up the crime, burying the body of a woman they accidentally hit. The guilt and the secret begin to tear their group apart as they navigate their professional lives as lawyers and public servants. Years later, the past comes back to haunt them when the victim's mother begins an relentless pursuit of justice. As the group faces internal betrayal, blackmail, and the moral weight of their actions, they must decide whether to continue protecting their lies or face the consequences of their crime. The series explores themes of justice, morality, and the lengths people will go to preserve their reputations.