Jedi Master Kit Fisto, Jedi Knight Nahdar Vebb, and a squad of clone troopers undertook a mission in 22 BBY during the Clone Wars to recapture Trade Federation Viceroy Nute Gunray, who had recently escaped from Republic custody. However, Confederate Head of State Count Dooku, displeased with General Grievous's recent failures in the war, used a Republic homing beacon to lure the Jedi and clones to the general's castle on the third moon of Vassek as a test for Grievous. Gunray deceived the Jedi and troopers through a holotransmission, and once they uncovered the ploy, Dooku contacted the Republic agents and put them on the trail of the "alternative prize" of Grievous.

The Jedi and their troops set a trap for Grievous and confronted the cyborg general once he arrived. However, Grievous was able to eliminate several clone troopers, and after sustaining injuries, escape to the castle's secret command center. Sealing off the exits, the Confederate general trapped the Jedi and clones inside his castle. While Grievous was repaired by his caretaker droid , the general pitted the Jedi and the remaining clones against the castle's defenses—a molten incinerator pit and the general's pet roggwart Gor . The clones were killed, but the Jedi were able to eliminate Gor. As Grievous resolved to personally confront the Jedi, Fisto and Vebb infiltrated the castle's command center. Vebb remained outside, however, and fought Grievous himself, but was killed by the general. After Fisto dueled Grievous on the castle's outer platform, the Jedi Master was able to escape.