Fraggles, tiny humanoid creatures about 18 inches tall [5], come in a wide variety of colors and have tails that bear a tuft of fur on the end. They live in a system of caves called Fraggle Rock that are filled with all manner of creatures and features, and which seem to connect to at least two different worlds that exist in different dimensions of time and space. Fraggles live a very carefree life, spending most of their time playing, exploring, and generally enjoying themselves. They live primarily on a diet of radishes and "doozer sticks" (see below) and are known to occasionally eat other vegetables. Fraggles have the ability to "share dreams"; if they touch their heads together before falling asleep, one can enter the dream of the other Fraggle. More than one Fraggle at a time can enter a single Fraggle's dream, provided all the participants' heads are touching. Deep in the caves of Fraggle Rock lives another group of Fraggles that are known to other Fraggles as Enemy Fraggles. (As shown in the episode "Fraggle Wars"). Enemy Fraggles live in a place they call Fraggle Cave. The Enemy Fraggles are dull and seem to be a lot like Doozers in a way because they both dislike Fraggles and both do not do a lot of fun stuff.
The series focused on one group of Fraggles in particular: Gobo (Jerry Nelson), Mokey (Kathryn Mullen), Red (Karen Prell), Wembley (Steve Whitmire), and Boober (Dave Goelz). They form a tight-knit group of friends, and each has a distinctive personality type.
Within Fraggle Rock lives a second species of small humanoid creatures, the pudgy, green, ant-like Doozers. Standing only 6 inches (150 mm) tall (knee high to a fraggle), Doozers in a sense represent anti-Fraggles; their lives are dedicated to work and industry. Doozers spend much of their time busily constructing all manner of scaffolding throughout Fraggle Rock using miniature construction equipment and wearing hardhats and work boots. No one but the Doozers themselves seem to understand the actual purpose of their intricate and beautiful constructions.
Often they accompany their building with marching songs and various doozer chants. To ensure that they always have a steady stream of work to do, Doozers build their constructions out of an edible candy-like substance (manufactured from radishes) which is greatly enjoyed by Fraggles. They actually want the Fraggles to eat their constructions because "architecture's supposed to be enjoyed" and also so they can go on to build again. This is essentially the only interaction between Doozers and Fraggles; Doozers spend most of their time building, and Fraggles spend much of their time eating Doozer buildings. They thus form an odd sort of symbiosis. In one episode, the flavor of the Doozer sticks is augmented[by whom?] by adding other flavors, such as tomato and mustard.
This symbiosis was part of an episode where Mokey called upon the Fraggles not to eat the Doozers' constructions - because they spend so much time making them. Fraggle Rock quickly filled with constructions and the Doozers had no space left to build. After running out of space the Doozers finally decided that it was time to move on to a new area because the Fraggles would not eat their construction, and there was even a tragic scene with a mother explaining to her daughter about how things don't always work out but that they would find a new place to live where their construction would get eaten. Overhearing this convinced Mokey that she inadvertently disrupted a vital symbiotic relationship through ignorant good intentions. As a result, Mokey frantically rescinded her prohibition and encouraged the Fraggles to gorge on the structures just in time to encourage the Doozers to stay.
At one point a series of Fraggle Rock books appeared, one entitled "The Legend of the Doozer Who Didn't." This book details the story of a Doozer who went against Doozer tradition when he stopped working and going to school. According to this book, a Doozer who doesn't becomes a Fraggle.
The series had several episodes that featured a Doozer as a main character, a young female named Cotterpin. She was performed by Kathryn Mullen.
Gobo's uncle Matt, known as Traveling Matt, has gone into "Outer Space" (what the Fraggles call the human world) to explore, and he sends postcards back to Gobo regularly. The name "Traveling Matt" puns on the special-effects technique for combining objects (such as spaceships and starry background): known as a traveling matte. Humans are known to Fraggles by the name "Silly Creatures", bestowed by Matt after observing and interacting with them in his travels.
In the North American version, the connection between Fraggle Rock and Outer Space is a small hole in the wall of the workshop of an eccentric inventor called "Doc", and Gobo must go out into Doc's workshop to retrieve the postcards from the wastebasket where Doc throws them. Doc remains unaware of the Fraggles' existence, but his dog Sprocket has seen them and attempts in vain to prove their existence to his master. Before becoming an inventor, Doc made his living as a barber.
Doc's true name was revealed in the last episode to be Jerome Christian (or Crystal, according to the official Encyclopedia Fragglia). In the second-to-last episode, he finally learns that the Fraggles exist and befriends them. Matt also returns home to Fraggle Rock.
Doc has a friend, Ned Shimmelfinnie. At first Sprocket hates Shimmelfinnie, who has a cat, Fluffanella. Sprocket makes a face and choking gestures every time Shimmelfinnie's name is mentioned. He stops doing this after Doc and Shimmelfinnie have a fight in episode 19 of Season One.
Doc also helps out Ms. Betty Ardath, who moves into his neighborhood in episode 44. She runs a bed-and-breakfast called "The Captain's Inn". Sprocket has a crush on her pet Airedale, Marigold, just as Doc has a crush on Betty.
On the outside of another exit from Fraggle Rock — through a well — live a small family of Gorgs, giant furry humanoids standing 22 feet (6.7 m) tall. The husband and wife of the family consider themselves the King (Gordon Robertson and Jerry Nelson) and Queen (Trish Leeper and Myra Fried) of the Universe, with their son Junior (Richard Hunt and Rob Mills) as its prince and heir, but to all appearances they are really simple farmers with a rustic house and garden patch. The second episode of the first season reveals that the Gorgs have never actually met anyone besides themselves in years ("I've never met a real subject before!"), suggesting that King and Queen of the Universe are self-imposed titles. The Gorgs regard Fraggles as pests, as they steal radishes. In one episode it is revealed that the Gorgs use radishes to make "anti-vanishing cream" that prevents them from becoming invisible. Thus, the three main races of the Fraggle Rock universe — Fraggles, Doozers and Gorgs — are all dependent on the radishes for their own particular reason. While the King and Queen consider the Fraggles disgusting vermin, Junior enjoys chasing, catching and keeping them like pets, much like a boy would lizards and bugs ("Look, Maw! I caught a Fwaggle!"). Junior is clearly lacking in friends, so it is arguable that he pursues the Fraggles just so he has someone to talk to. The Gorgs were developed by art director Douglas Cook in the Isle of Wight.
As the series progresses, we learn that at the beginning of time a God-like character placed the Gorgs to rule over the universe until he returned. We also get a few various visitors from the rest of the Gorgs' world. In one episode, a frog-like con-man (Wander McMooch) temporarily tricks the Gorgs out of their castle so he can raze the forest to build a village. This implies that many other people (and indeed, other Gorgs) live in that world... enough to fill a village, anyway. This conflict is resolved when the con-man finds out there are hundreds and thousands of Fraggles living around the Gorg's castle. He seems to view Fraggles to be pests, like rodents, and gives back the castle. This is important because it alludes that Fraggles are scattered all over the world the Gorgs live in, are generally considered to be pests by everyone (not just Ma and Pa Gorg) and most of all, it is rare to find such a large collection of Fraggles in one place. It's also sort of funny because it means that the self-proclaimed rulers of the universe really live in a run down, pest infested hole in the wall.
The Trash Heap, a wise being (referred to as an "oracle") serves as the garbage dump of the Gorgs. She and her heckling heralds live near the Gorg's garden, and she gives the Fraggles guidance and advice, which the Fraggles regard with reverence, but not worship. She also appears to have some magical abilities (specifically telepathy and the ability to teleport items or Fraggles), though she does not use them often. Sometimes she knits to pass the time. Jerry Nelson voiced the Trash Heap.
The heralds of the Trash Heap, they often introduce her as the "all-knowing, all-seeing Trash Heap!" They supply humour, bad jokes, and puns. Although Gunge portrays himself as the brains of the pair, neither ever really prove to be a great help. They watch over the Trash Heap; if they left for a long time she would begin to die out. When she finishes speaking, they announce, "The Trash Heap has spoken! Nyeah!" Philo and Gunge did get two episodes of the series devoted to them: "Home Is Where The Trash Is" and "Gunge The Great & Glorious". After Fraggle Rock ended, Philo went into retirement, but Gunge appeared on Dinosaurs and Mopatop's Shop. Philo was played by Dave Goelz and Gunge was played by Richard Hunt.