The show focuses on a group of friends aged between 8-15 who are sucked into the "Realm of Dungeons & Dragons" by taking a magical dark ride on an amusement park roller coaster. Upon arriving in the realm they meet Dungeon Master (named for the referee in the role-playing game) who gives each child a weapon to defend themselves with. The children's main goal is to find a way home, but they often take detours to help people, or find that their fates are intertwined with that of others. The group come across many different enemies, but their primary antagonist is Venger. Venger is a powerful wizard who wishes to rule the realm and believes the power from the children's weapons will help him to do so. Another recurring villain is Tiamat, who is a five-headed dragon and the only creature Venger fears. Throughout the show, a connection is suggested between Dungeon Master and Venger. The final un-produced episode would have revealed that Venger is the Dungeon Master's corrupted son, and would have explained that the children were brought into this realm to help redeem Venger and to restore balance to their world.
At 15, he is the oldest of the gang, along with Eric, and a natural leader. He is brave and noble, never loses his head, even being in danger. Hank is a Ranger, with a magical bow that shoots magical arrows of glowing energy. These arrows could be used in many different ways such as a climbing tool, to hurt enemies, to bind them or to create light.
The cavalier is the spoiled child, originating from a rich home. On the surface Eric is the big-mouthed coward of the show, and he also fulfills the role of the comic relief character. Despite his egotism, selfishness, and snobbery, Eric is potentially also the most realistic character, complaining about the dire situations in which he is involved and voicing concerns which might be common to inhabitants of our world transplanted to the Realm. Despite his cowardice and reluctance, Eric has a well-hidden heroic core, and constantly saves his friends from danger with his magical shield, which can project a force field.
Diana is a beautiful and brave 14-year-old girl. She is an acrobat, and an outspoken and tomboyish member of the group. She carries a magic staff which can shift in length from as short as a few inches to be easily carried on her person to long as six feet to be used as a defensive weapon or as an aid during various acrobatic moves. Furthermore, if the staff is broken apart, Diana simply has to touch the severed pieces together at their break point and they will completely reunite as one unit. She is skilled at handling animals, and is a self-assured, confident person. These qualities make her the natural leader in the absence of Hank. It is mentioned that Diana is chosen as the acrobat because in her real world she is an Olympic-level gymnastics practitioner.
14-year-old Albert, better known as Presto, is the wizard. Presto fulfills a role of the well-meaning, diligent, but hopeless magician. He suffers from low self-confidence and nervousness, which manifests in the use of his magical hat. He is able to pull an endless succession of various tools from it; but often these will be, or appear to be, of little use. There are also numerous instances when the whole group is in danger, whereupon Presto will draw from his hat precisely what is needed in order to save all of his friends.
As the thief, Sheila has a magical cloak which, when the hood is raised over her head, makes her invisible. Although Shelia is often shy and nervous she will always display bravery when her friends are in trouble, especially her younger brother Bobby. Sheila is also the first to point out the flaws or dangers of the group's plans. In both the Spanish versions of Spain and Latin America, Sheila is called a mage or illusionist.
Bobby is the youngest member of the team; the characters celebrate his eighth birthday in the "Servant Of Evil" episode but says he is "almost ten" four episodes later in "The Lost Children." He is the barbarian, as indicated by his fur pants and boots, horned helmet, and cross belt harness. He is Sheila's younger brother; in contrast to her, Bobby is impulsive and ready to run headlong into battle, even against physically superior enemies usually resulting in one of the others moving him from harm's way. He has a close relationship with Uni and is often reluctant to leave her when they discover a way home. Bobby carries a magical club, which he regularly uses to trigger earthquakes when he strikes the ground.
The group's friend and mentor, he provides important advice and help, but often in a cryptic way that does not make sense until the team has completed the quest of each episode. It is the Dungeon Master who supplies the companions with their weapons and clues for their numerous opportunities to return home. As the series progresses, from his repeated displays of power, it begins to seem possible and later, even probable, that the Dungeon Master could easily return the companions home himself. This suspicion is confirmed in the script for the unmade series finale, "Requiem", wherein the Dungeon Master proves he can do just that, without any difficulty. In some episodes, including "City at the Edge of Midnight" and "The Last Illusion", realm inhabitants display great respect or nervous awe of Dungeon Master.
Uni is Bobby's pet, a baby unicorn, which Bobby discovers in the first episode and retains as his companion throughout the show. She has the ability to speak, though her words are not quite discernible; she usually is heard echoing Bobby when she agrees to his opinions. As seen in the episode "Valley of the Unicorns", Uni also possesses the potential for the natural unicorn ability to teleport once a day, and has accessed this power through tremendous concentration and effort; it is intimated that she is still too young to use this ability regularly.
The main antagonist and the Dungeon Master's son (as revealed in the episode "The Dragon's Graveyard" and again in the lost episode "Requiem"), as well as Kareena's brother ("Citadel of Shadow"), Venger is an evil wizard of great power who seeks to use the children's magical weapons to bolster his power. Though described as an evil force, comparable to the devil, it is occasionally hinted that he was once good, but fell under a corrupting influence. This is later revealed to be true in the unmade finale "Requiem", when Venger is restored to his former self.
A shadowy demon, he is Venger's personal spy and assistant. He often informs Venger about the kids' current quests.
Venger's arch-rival is a fearsome female dragon with a reverberating multi-level voice and five heads that "breathe" different attacks such as ice, electricity, and fire. Although Venger and the children both avoid Tiamat, the children often use her to their own ends such as making a deal with her in "The Dragon's Graveyard" to thwart Venger.