While waiting for the school bus, Stan's dog, Sparky, shows up. Stan claims that his dog is the toughest dog in South Park, but Cartman thinks Sylvester is the toughest. Sparky and Sylvester circle each other and prepare to fight, when suddenly Sparky jumps on top of Sylvester, attempting to hump him. Apparently, Sparky is a "gay homosexual", as Cartman puts it, leaving Sylvester running away yelping.
At football practice, Stan's Uncle Jimbo and his buddy Ned show up (representing the South Park alumni) asking the coach, Chef, if the boys can beat the spread of 70 points. Impressed by a catch, Jimbo and Ned run off to the bookie where Jimbo puts $500 on the South Park Cows, to cover. Unsure of wanting to rely on Stan, Jimbo and Ned seek a backup plan and learn that John Stamos' brother Richard will be singing "Lovin' You" at halftime.
After practice, Sparky shows up and mounts another dog, Rex, who also runs away yelping with his tail between his legs. The next day, after class, Stan asks Mr. Garrison to tell him what a homosexual is. Mr. Garrison's response is that, "Gay people are evil. Evil right down to their cold, black hearts, which pump not blood, like yours and mine, but rather a thick, black venomous oil." Stan sets on a quest to make his dog more masculine, hoping to prevent him from being gay, not realizing that Mr. Garrison was actually trying hide his own sexuality rather than giving an accurate description of gay people. His first attempt, presenting Sparky with Fifi, a female poodle, fails miserably when Sparky steals Fifi's Diamond-encrusted collar, only adding to the fact that Sparky is a homosexual. Thinking that homosexuality might not be bad, Stan calls up Jesus on his show Jesus and Pals to ask him what he thinks of homosexuality. However, before he can answer, the show suddenly ends and moves onto the next show. Frustrated, he rants about wanting a butch dog, a Rin Tin Tin. Sparky overhears this and runs away, ending up at Big Gay Al's Big Gay Animal Sanctuary.
As they talk to Carl, a bomb and explosive expert, Jimbo and Ned's plan is revealed: to blow up the opposing team using a sonic triggering device as Richard Stamos hits the high F note in the song. They attach the bomb to Middle Park's mascot. At halftime, Richard Stamos fails to hit the note, upsetting Jimbo and Ned, who shout that he isn't as talented as his brother.
Worried about his dog, Stan looks for him and finds him at the Big Gay Animal Sanctuary. Here, Stan learns from Big Gay Al that homosexuality has been around for a long time, and Stan eventually accepts his dog's homosexuality. Returning to the game in progress, Stan steps in as the quarterback, passing the ball to Kyle for a touchdown that beats the spread as time runs out. In his interview after the game, Stan tries to tell the people of South Park about the Big Gay Animal Sanctuary and that "it's okay to be gay."
He attempts to lead the people to the site of the Big Gay Animal Sanctuary, but it is mysteriously missing; people's runaway pets, however, return. As everyone dissipates, Big Gay Al appears to Stan, thanking him for bringing everyone to reclaim their animals before he disappears as well.
Although the Cows beat the spread, Richard Stamos shows up to prove he can hit the high note that he missed earlier, which triggers the bomb and blows up the Cowboys' mascot.