Stumbling upon my stepsister Penelope in our home, I couldn't believe my eyes. She was in her sexy lingerie, riding some guy I didn't recognize. I grabbed my camera, filming in POV as I confronted her. She tried to hide her face, but I zoomed in, capturing her shame. As the guy fled, I demanded answers. Penelope confessed, tears in her eyes, her body trembling in that revealing outfit. I couldn't help but feel a dark thrill, my cock hardening at the taboo scene I'd just witnessed.