King of the Hill: Season 2, Episode 11

2 - 11: The Unbearable Blindness of Laying

Hank's mother comes to visit for Christmas with her new boyfriend, Garry. When Hank walks in on his mother and Garry having sex, he goes blind. Garry figures out the problem, and tries to help regain his sight, and they end up at a Faith Healing Church for answers.