The Duel on Hesperidium was a vicious fight that occurred in the year 40 ABY, between Jedi Master Mara Jade Skywalker, and Lumiya, Dark Lady of the Sith. Having tracked Lumiya through the Force to the resort moon of Hesperidium, Skywalker engaged her fellow former-Emperor's Hand in combat, intent on eliminating the Sith for threats made against Skywalker's son Ben.
Both women displayed their finesse with their weapons; Lumiya with her signature lightwhip, and Skywalker with her own lightsaber. Skywalker quickly gained the advantage, managing to land several critical blows before she executed what she believed to be the killing blow. Lumiya's life was spared, however, when her recently-acquired Meditation Sphere intervened on her behalf to disable Skywalker. Reeling in surprise at the sudden and unexpected attack, Skywalker was helpless under the strength of Ship's attack, and watched in anger as Lumiya escaped her wrath yet again.
It was only after a conversation with her son Ben did Mara realize she had been jumped by Lumiya's Ship, and that the Sith Lady was also secretly in league with Skywalker's nephew Jacen Solo, leader of the Galactic Alliance Guard.
Jedi Grand Master Luke Skywalker, and his wife Mara Jade Skywalker, were aware that Lumiya, self-proclaimed Dark Lady of the Sith, was actively spreading her dark side influence throughout the galaxy once again. Concern had also arisen between them that Lumiya was hunting their son, Ben, and was doing so through an inside connection to the Galactic Alliance Guard, the secret police of the Galactic Alliance. They even suspected that Lumiya's influence had spread so far as to enthrall their nephew Jacen Solo, leader of the GAG.
Lumiya had indeed been in collusion with Solo; however, when Mara questioned Solo about Lumiya's involvement in GAG affairs, he denied any such notion, while secretly becoming concerned that his aunt would soon discover the truth in her assumptions.
Lumiya then devised a plan to draw the Skywalker's attention away from her apprentice Solo, by taking a pair of Ben's boots and leaving them outside the Skywalker residence. Luke found them, and immediately deduced that Lumiya had deliberately placed the boots where he would be sure to find them. Because of this, it was decided that Mara should find and confront Lumiya, while Luke himself monitored Jacen's actions. Mara Jade Skywalker immediately set out in search for the Sith Lady Lumiya, following a trail through the Force that pointed in the direction of Hesperidium, a resort-moon in the Coruscant star system.
She immediately felt Lumiya's dark Force aura, and ignited her lightsaber as she began searching the surrounding hotel area for her quarry. Instead of finding Lumiya, however, Skywalker encountered the Sith's ship as she rounded the corner, one which resembled a large, disembodied eye. Communicating through the Force, the Sith ship beckoned Skywalker to enter; an invitation which she cautiously accepted, fully expecting to find her quarry inside. She entered the empty vessel, had a brief discussion with the Meditation Sphere, and placed a tracking device inside before Lumiya herself finally appeared outside between a few parked ships. The two women silently acknowledged each other, and engaged in intense combat.
Skywalker leaped at Lumiya with her lightsaber drawn, managing to slice off a corner of the Sith's headdress. In turn, Lumiya quickly whirled her lightwhip in Skywalker's direction, but missed her target after being Force-pushed away by the Jedi Master. Skywalker evaded as Lumiya lashed her whip again, this time just barely missing Skywalker's head. As Lumiya raised her arm for another strike, Skywalker shot her in the shoulder with her blaster, hitting one of Lumiya's cybernetics, but with little effect. Skywalker then quickly lunged at Lumiya's durasteel legs, the impact of which filled her mouth with blood, while at the same time toppling Lumiya. She then head-butted her cybernetic jaw causing more pain to herself. In a surprise tactic, Mara turned off her lightsaber, only to reignite it in Lumiya's chest. Ship then intervened, and Mara felt a metal coil wrap around her neck and throw her backwards. Mara hit the ground, looking up in time to see Lumiya's boots fly past her face. She then looked up to see the Sith Meditation Sphere fly away, with Lumiya safely inside.
As the Jedi Council were discussing what action should be taken about the recent coup and the Mandalorian alliance with the Verpine, Mara entered the chamber still bearing her gruesome battle wounds. After assuring everyone she was fine, she informed them of Lumiya's new ship and that she would be ready for the next time she fought the Dark Lady of the Sith.
Ben Skywalker later learned from the Ship that it intervened because its purpose was to train apprentices to fight. It would let the two fight but not let either one be killed. However, both combatants died not long after the duel. Soon after, Jacen Solo killed Mara on Kavan, and Luke Skywalker killed Lumiya on Terephon.