Deep within the inhospitable wilds of the planet Arkania, a Jedi Master named Arca has established a training compound for Jedi knights. Here Ulic Qel-Droma, Arca's most fearless - and certainly the most bold - student, is practising his lightsaber skills against a training droid for which Arca and two other jedi knights, Tott Doneeta and Ulic's brother, Cay, watch on. Ulic, despite his skills, allows over-confidence to get the better of him and loses this training battle for which Arca instructs "Let the force be your strength."
As Cay attempts to repair the droid, Master Arca instructs his students to be an audience to his story. As they sit down Arca tells them of Onderon, a half-civilised world, which has recently been discovered by galactic explorers. "One of the four moons of Onderon, Dxun, has an atmosphere of its own and contains monstrous and savage flying creatures. Eons ago the atmospheres of Onderon and Dxun would briefly touch allowing these creatures to escape the confines of the moon and enter the atmosphere of Onderon. The peaceful tribes on Onderon were perfect fodder for the creatures but soon the Onderonians learnt to defend themselves, they began to hunt and build weapons. Eons later tribal culture evolved into true civilisation which had developed in the form of Iziz, a great walled city. The city kept everyone safe from the Dxun creatures while outside these walls remained a savage outland. Lawbreakers within the city were punished by being exiled into these outlands where they quickly become food for these ghastly creatures. Over time though, these outcasts learnt to defend themselves fom the Dxun beasts and some even managed to control them. What eventually resulted was a state of civil war between the people of Iziz and the outcasts."
What Arca is getting at is that he has been assigned to watch over the Onderon system. But he is not going himself, rather he is sending his three apprentices to go to Onderon and assist the Onderonians who have asked for help. The three Jedi knights are stunned yet excited - at last, after years of training, they are to go forth on a mission of justice. Ulic, along with Cay and Tott Doneeta, farewell Master Arca and aboard the "Nebulon Ranger."
Emerging from hyperspace, they make their way to the city of Iziz on Onderon but not without some difficulty as they are attacked by beast riders. Refusing to fire - they are here on a mission of peace - they manoeuvre around the creatures and land within the great-walled city.
Disembarking, the three youths are met by Novar, the Onderonian Minister of State. As they introduce themselves however, Tott Doneeta is taken captive by Novar's guards under Novar's request that "alien races are not allowed within the royal citadel and he is to be placed in immigration for interogation". Ulic and Cay are quick to defend their friend's honor and ignite their lightsabers as a warning to release him. Novar warns them that mortal threats from jedi will cause "severe political repercussions".
Following this they are taken to Queen Amanoa who allows Tott Doneeta (or as she calls "worm head") to be released. Amanoa expresses her disappointment in receiving three "untutored" youths rather than the great Jedi Master as she had been informed. Nevertheless, they are introduced to the Queen's daughter, Galia, whom Ulic has a instant fondness for. Their meeting is cut short however, with the news that several beast riders have broken into the citadel. Ulic, Tott and Cay find themselves in action quicker than they thought they would as they attempt to defend the city from its attackers. As they do so, a bulk of the "beast warrior commandos" disembark their flying beasts and enter the palace. Ulic sends Cay and Tott after them but when they finally reach the royal quarters they discover that Galia has been abducted.
Queen Amanoa curses the Jedi knights for this event and orders them to find her. Ulic immediately obeys but Cay and Tott believe they should consult Master Arca first, sensing powers of the dark side within these strange people.
Ulic, Cay and Tott Doneeta venture into the vast wastelands of the planet in search of Galia, but their mission is slightly thwarted when their ship is shot down and several beasts surround the cruiser.
Luckily, Tott Doneeta has a unique jedi power of understanding beast languages and they become honorary riders to the beasts who take them to the location of the kidnapped Princess.
Upon arrival they interupt the wedding of Oron Kira, son of the Beast Lord Modon, and Princess Galia. The Jedi take to rescuing Galia, only to find that she wishes to marry Oron and that the abduction was planned.
Ulic discovers that the city of Iziz is strong with the dark side of the force with many inhabitants worshipping the ways of Freedon Nadd, a dark lord of the Sith who ruled the city centuries ago. He takes Galia and Oron back to Iziz hoping a marriage between the two waring clans might bring peace, only to find Queen Amanoa turn to rage and summon the full power of the dark side. Meanwhile, the beast-lord Modon, has rounded up his warriors and they attack the City.
As the battle commences it looks as if the sides are even but Queen Amanoa visits the mausoleum of Freedon Nadd where she gives herself completely to the dark side and begins to manipulate Modon's warriors into defeat. Meanwhile Cay, after confronting the Queen, is attacked by her guards and in the battle he loses his arm. Ulic comes to his rescue but brave old Cay tells him not to worry, after all it's only an arm. Seeing an expired XT-G Model Droid, he takes the droids arm and uses it for his own.
As the battle between the beast warriors and the Onderonians wages on, Modon's army begin to face defeat due to Amanoa's spell. But someone else, also experienced in Jedi Battle Meditation, has arrived on the battleground and begins to give the beast warriors the winning spirit they need. As Ulic and the others watch the battle from a distance they see the strange turnaround and recognise the new arrival to be Master Arca.
Slightly disappointed with Ulic's efforts, Arca leads his students to the tomb of Freedon Nadd where Amanoa stands, continuing her worship. Arca uses his power to extinquish the dark side, which kills Amanoa in the process.
Galia is married to Oron and the warring tribes unite but Arca warns that the dark side has not completely left this world and asks Ulic and his other apprentices to stay on a while longer to ensure peace