In the year 10 ABY, subsequent to Kyle Katarn's disappearance on Dromund Kaas, a Sith world that served as the ancient capital for the Sith Empire and the base of the Prophets of the Dark Side, Mara Jade embarked on a quest: to locate Kyle Katarn.
Kyle Katarn, a commander within the New Republic and a Jedi apprentice, vanished while probing the ancient Sith ruins located on the planet Dromund Kaas, an event that occurred after the Battle of Altyr V. Following her successful retrieval of a stolen Jedi holocron, Mara Jade, a fellow Jedi, volunteered to undertake a search for Katarn situated on Dromund Kaas. Unbeknownst to her, Kyle had been swayed by the Dark Force Temple's influence on the Sith world and had succumbed to the dark side of the Force.
Mara Jade arrived in a jungle clearing near the Dark Force Temple, where she discovered that all of her weapons, except for her lightsaber, were rendered inoperable. She then proceeded toward the Dark Force Temple. She employed the Force to bypass the Watchers, battled through the dangerous indigenous creatures, and eventually encountered a Force-generated doppelganger of herself. After vanquishing the Sith apparition, Mara gained entry to the temple, where she had to defend herself against the mutated Noghri, Sith Jedi Statues wielding lightsabers, and Vornskrs guarding the ruins.
Ultimately, she located Kyle Katarn deep within the Temple's core. He was completely consumed by the dark side. He rejected her offer of assistance, attacked her with Dark force energy, and retreated further into the catacombs. Mara pursued Kyle, facing numerous trials and adversaries, including resurrected Sith undead warriors. She descended into the ruins and confronted Kyle in the temple's heart. Instead of engaging in combat, she turned off her lightsaber, placing herself at Kyle's mercy. Unable to harm his friend, Kyle realized he could not continue down the dark path and returned to the Light side of the Force, departing Dromund Kaas alongside Mara.
In the wake of these occurrences, Katarn determined that he was unable to continue his training independently. He later accepted Luke Skywalker's guidance and became a member of the New Jedi Order. Skywalker made the decision to keep the location of Dromund Kaas a secret to prevent its corrupting influence from affecting other Jedi.