In the eight years since the fall of the Empire, Luke Skywalker has trained a new group of Jedi Knights, among them the warrior woman Kirana Ti, the sky-hermit Streen, the scholar and lore-master Tionne, and his greatest student, the brash Kyp Durron. Once trained, a Jedi must go where he is needed, to defend the New Republic and use the light side of the Force to help those in need. On Coruscant, Chief of State Leia Organa Solo receives a desperate message from miners on the harsh world of Corbos. They have awakened something in their excavations and have come under attack. Luke sends Kyp Durron and the young clone Dorsk 82 to investigate and offer whatever assistance they can. But when Kyp and Dorsk 82 arrive on storm-swept Corbos, they find only an empty mining colony, and the scene of a terrible disaster.

After receiving a distress call, Kyp Durron and Dorsk 82 come to Corbos, only to find they are too late. The colony is destroyed leaving only evidence of a slaughter...and a monster! Kyp slips away at night to track down the hideous beast. When Dorsk 82 awakens to find him gone, he immediately summons help, but before they can arrive, Kyp, alone, finds the monster.

Kyp Durron arrives on the mining world of Corbos only to find the entire colony destroyed. There are no signs of life but Kyp can still hear the psychic outcries of the colonists. He is drawn toward the Leviathan of Corbos, a beast that he finds has devoured the colonists, and yet trapped their minds and spirits. And it's up to Kyp to defeat the Leviathan on his own!

Kyp Durron thought he had destroyed the Leviathan that laid waste to the mining colony of Corbos. But he was wrong. He killed its offspring and now the mother of the Leviathan is looking to take revenge on the Jedi. Now Kyp and the rest of the Jedi Academy must face a threat even larger than they had first imagined.