The Confrontation: The Knight finds the Queen. She has lost her mind and is about to trigger a "final spell" that will destroy everyone—including her daughter.
The Impossible Choice: To save the Princess and the kingdom, the Knight has to stop the Queen.
The Double Death: As the Knight lunges to strike the Queen, a Shadow Kingdom assassin (or a trap) strikes him from behind.
The Moment: His sword pierces the Queen's heart at the exact same second the life leaves his eyes.
The Last Look: They both fall. The Princess runs into the room just in time to see the two people who defined her life—the one who gave her life and the one she gave her heart to—die together.