Hank's unique health condition threatens his ability to compete in the Durndle County Mower Races
When Dale tells the guys about the 1st Annual Durndle County Mower Races, Hank, Bill and Boomhauer decide to throw their mowers into the ring and compete. Meanwhile, Hank's back goes out again and Peggy begs him to see a doctor. When he finally gives in, he is shocked to discover his true ailment. Hank suffers from a genetic disorder called Diminished Gluteal Syndrome (DGS). Basically, Hank has no butt and it puts added stress on his spine.
With the aid of an orthogluteal (i.e. fake butt), Hank is ready to resume his mower training. However, the guys soon learn of his "condition" and Hank becomes the butt of their childish gags - which culminate with his silicone cheeks suspended from the electrical line. Hank gives up on the mower race until Peggy tricks him into attending a DGS support meeting. Once his confidence returns, Hank is back in the race - and ready to kick mower butt!