Fraggles, tiny humanoid creatures about 18 inches tall, 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 loving life. They live primarily on a diet of radishes and "doozer sticks" 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. 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, Mokey, Red, Wembley, and Boober. They form a tight-knit group of friends, and each has a distinctive personality type.