Flange Doozer develops a new tomato extract to add to the Doozer sticks, and Modem Doozer adds mustard powder. The Fraggles think the new Doozer sticks are delicious, but when Flange and Modem fight over which additive is better, Doozer society erupts into competition. The only way to decide which is the better-tasting Doozer stick is to ask the first Fraggle who comes along....who turns out to be the indecisive Wembley Fraggle.
Meanwhile, Doc observes an ant farm. He is soon interrupted when Sprocket barks at a dog belonging to a new neighbor since Ned Shimmelfinney gave the new neighbor's dog a bone.
The Doozers all work together in a society that values cooperation in order to further the common good (which is very much contrary to the Fraggles, who place a high value on individualism and independence). The Doozers pride themselves on the good work that they do, but no Doozer is allowed to take personal credit for his or her work -- that would mean that they thought their work was better than everyone else's, which would be destructive to the communal spirit. Competition is seen as a vice that occasionally afflicts Doozers. Again, this is very unlike the Fraggles, who love to have races and competitions, and who take pride in their individual jobs and passions.
Doozers are apparently very fast healers. The night before the contest (because of an offscreen fight with Wrench), Cotterpin has a bandage on her nose, a cast on her right antennae, and she's using a crutch to walk. The next day these injuries are completely gone.
In the first season, the Doozers were very much background figures, but the producers made an effort to develop the Doozer world in the second season, with three episodes focusing specifically on Doozer society. This episode reintroduces Cotterpin, the young architect-in-training who idolizes the Fraggles, her teacher the Architect, her parents Flange and Wingnut, and her friend Wrench. The three episodes add a lot of depth to what we know about the Doozers, and offer an interesting contrast to the Fraggles' playful utopia. Both societies have irreconcilably opposite value systems, but both are presented as workable. The producers never push one worldview over the other (although they do clearly focus more on the Fraggles), and they do not suggest that the characters or the viewers have to choose which one is better.
The Doozers always stay underground. They even harvest their radishes in mines. So where did they get mustard and tomatos? That grows above-ground.