The initial strike by the Jedi Coalition against Jacen Solo, who was both the co-Chief of State for the Galactic Alliance and a Sith Lord, was the Undercity Ambush. The original strategy involved capturing or neutralizing Jacen, but this was revised to planting a tracking device on Solo when the initial goals were deemed unrealistic. The ambush proved unsuccessful, resulting in Thann Mithric's death at Darth Caedus's hand and Kyle Katarn, the renowned Jedi Master, narrowly escaping death. Nevertheless, the Jedi succeeded in attaching the tracking device to the Dark Lord.
Following the Devastation of Kashyyyk, Luke Skywalker tasked Kyp Durron with devising a plan to confront Jacen Solo. Subsequently, Kyp informed Luke of a scheme involving a four-Jedi team, accompanied by a guide, to ambush and capture Solo within Coruscant's undercity as he entered or exited the Senate Building. To divert pursuers during their escape with the captured Chief of State, a droid-piloted shuttle would be employed. Kyp conveyed to the Grand Master that if capturing Jacen proved unfeasible, they would eliminate him to prevent further harm to the galaxy. Luke reluctantly consented and requested a meeting with Seha Dorvald, the team's guide through the undercity. Her loyalty was questioned due to her assistance in Ben's escape from the Jedi Temple under Jacen's orders, as well as providing Jacen with intelligence on the Jedi. She confessed her actions upon learning about the Massacre on Ossus. However, after discussing the matter and learning about her conduct during the Invasion of the New Jedi Temple, Luke accepted her. Kyp advocated for Luke to lead the mission, but Luke declined. Luke recognized that he would act out of hatred, and that Ben would follow his example and be lost to the darkness. Instead, he designated Jedi Master Kyle Katarn as the team leader.
The Jedi team, consisting of Katarn, Jedi Knights Valin Horn, Thann Mithric, Kolir Hu'lya, and guided by Seha Dorvald, navigated through the undercity's waste pipes to reach their assigned positions. After several hours, a convoy of three airspeeders appeared. One was a black GAG speeder, the second a heavily armored civilian speeder, and the third a GAG troop carrier. The convoy halted, and troops began securing the perimeter. Subsequently, the civilian speeder opened, and a YVH droid emerged, carrying a crate containing Solo's daughter Allana, followed by Jacen himself. As the group proceeded towards the Senate Building, Katarn initiated the attack.
The conflict commenced with the Jedi strike team launching grenades at Caedus's forces, temporarily blinding them. YVH-908 escorted Allana to safety. Subsequently, the four Jedi confronted Jacen, with Katarn offering surrender, which Solo promptly refused. Realizing the potential for being outmatched, Katarn instructed Seha to remain behind and attach a tracking device to Jacen's cloak to monitor his movements, in case the Jedi failed.
Katarn initiated the duel with a strike that Caedus deflected. Caedus used the Force to push Hu'lya into Mithric. Katarn attempted another strike, but Caedus evaded the blade and kicked Valin Horn in the chin. Katarn nearly kicked Caedus in the head, but he managed to partially avoid it, catching a scrape on his cheek. Caedus retaliated by slashing at Katarn's leg, but his strike was blocked by Kolir. At that moment, the Jedi escape shuttle entered the plaza, closely pursued by three GAG airspeeders.
Caedus attacked Horn, causing him to fall into Mitric's path. As the two Jedi collided, Caedus used the Force to push Hu'lya into Katarn, who threw his lightsaber at Jacen in order to catch Hu'lya. Caedus swatted away the lightsaber and threatened to torture the Jedi if they didn't reveal the location of their secret headquarters. Hearing this, Katarn made one final plea to Jacen to realize his actions, asking if he knew who he was anymore. The Sith Lord responded that he did, and it was the Jedi who had no idea who he was now.
Caedus used the Force to pull Kolir, blocking an incoming attack from Mithric and Horn. Katarn advanced towards the Sith Lord but remained unaware of the GAG speeders attacking their escape shuttle overhead. Caedus exploited this by pulling down a speeder and launching it down toward the Jedi Master. The speeder hit Kyle in the back and knocked Kolir to the ground. Katarn flew forward and slammed into Caedus, as Caedus buried the hilt of his lightsaber into Katarn's chest. Seha used the chaos to her advantage and merged the patch with Caedus' cloak as the three remaining Jedi charged Solo. As Seha left, she pulled Master Katarn to safety.
The GAG troopers' sight had begun returning and they fired at Mithric and Horn. Valin deflected the bolts at Caedus, grazing his leg. Mithric then charged Caedus as he fell and began to beat down his parries. Mithric deflected more and more blaster bolts towards him. Caedus deflected one bolt into Mithric's chest, then decapitated him with a single lateral blow. After sharing a few words with Horn, Caedus watched as the Jedi fled.
Seha, Horn, and Hu'lya, carrying an injured Kyle Katarn, managed to escape through the undercity and make it back to the Jedi hideout. Caedus was disappointed that he could not find the body of Kyle Katarn, and picked up Mithric's head for a moment. Kyp Durron later informed Luke of the failed ambush and the success of the tracking device. This device would help the Jedi locate Jacen before the Battle of Centerpoint Station, but it was eventually discovered by Patra Tebut.