Red wants to be a leader, so she starts a Helping Club -- but when Gobo is elected the leader of the club, Red storms off and creates another. She makes up a lot of strict rules for her club and ends up excluding everyone except her one member, Cotterpin Doozer.
Meanwhile, Sprocket (having been rejected from the Top Dog Club) agrees with Doc to form the Underdog Club. Yet Doc is quite picky about what kind of members he wants to join.
The Doozers "mine" their radishes from underground, so they never see the Gorgs in their garden. So far in the series, Doozers and Gorgs have only seen each other once before. In Season One episode The Great Radish Famine, Flange Doozer (along with Mokey) meet a headless Junior Gorg in the Gorg garden in order to fulfill the Trash Heap's mandate and have the radishes restored. It's not clear why Flange never shared news of his Gorg encounter with the other Doozers or his daughter, Cotterpin, who has never even heard of Gorgs.
This episode is another element in the move to develop the Doozers this season. Last season, Doozers didn't talk to Fraggles, but now Cotterpin is presented as part of the landscape, a friendly Doozer who can interact with the Fraggles.
When Doc and Sprocket plan the rules for Sprocket's dog club, Doc says: "First rule of your club is no dogs that yap. That automatically eliminates Fred, Ginger, Angel, Mortimer, Mugsy, Rowlf..." Sprocket is very upset that Rowlf is excluded.
Karen Prell had to have emergency surgery during the filming of this episode, so Red is actually being puppeteered by Steve Whitmire. Karen dubbed the voice over later. 
UK version: The Captain tries to form a birdwatchers' club, but only Sprocket will join. Uncle Traveling Matt discovers a way to control a species of big yellow creatures: just yell "Taxi!" and they'll stop.