Okay, a woman who works with kids who have been abused finds out that her own son has been abused. He tells her that it was their priest from their church, and prelim DNA evidence confirms that is the case. The woman does not want her young son to go to trial as she knows from experience how the kids suffer and how hard it can be to get the case to stick.
So on the first day of the court, she smuggles a gun into the courtroom, and shoots the man concerned several times and kills him, her plan is to pretend to be crazy to get off with it.
Then the DNA is investigated further and it turns out that the priest had bone marrow donations from his brother when he was younger, so it was actually his brother who had abused the young boy, she'd killed an innocent man.