Mordred shoved open the door to the throne room with his shoulder, and the first thing Guinevere saw was his long dark hair matted with blood. The green eyes that reminded everyone of his father were narrowed to slits, and his black armor was caked in gore. If she had conjured up an image of death in her mind, this might well have been it.
"Kneel," he growled. "Kneel to your King."
Though she knew it might well mean her death, Guinevere held her head high.
"My King is Arthur, and when he returns-"
"When he returns from chasing a fairy tale goblet dreamed up by a madman," Mordred broke in, "he will find his kingdom in ashes and the rightful heir upon the throne." Stepping forward, he seized Guinevere's chin in his hands, turning her head so she was forced to look him in the eye. "But then, you were never the faithful Queen to him, were you?"
"How dare you!" she said. "How dare you spread lies even now!"
Mordred struck her with an armored fist and she stumbled to the floor. Her cheek was bleeding, but even so, she knew she had won a small victory. She had said something he did not expect.
"Are you trying to claim purity?" he demanded. "At this hour? Everyone knows about you and Lancelot, everyone but your foolish husband. Say it!" He seized her by the back of her copper hair. "Say you were unfaithful, no more loyal than me!"
"It- it is not true," she said through the pain. He twisted her hair, but she managed (just barely) not to cry. "It is true, I looked at him as a married woman should not. It is true, we spoke to one another in private, and there were times I had thoughts about- about what might have been. But I never touched him. Kill me if you wish, but it is the truth."
The pain subsided for a moment as Mordred's hands went to her chin again, and he gazed into her eyes. "By the devil", he whispered. "I think you might be telling the truth! How appropriate, then, that this will be your first time committing adultery."
Guinevere's stomach tied in a knot. It was what she'd feared, but some part of her had hoped he would not go through with it. His own father's wife! A part of her wished that he had simply slit her throat and had done with it all, while another part gasped in relief that her life would be prolonged, even for an hour.