This mission to Omphalos was a mission undertaken five months after the outbreak of the Clone Wars.
The mission was a covert operation under the command of General Mace Windu.
Arriving on a LAAT/i gunship, the objective was to stop a weapon being developed for Count Dooku. The weapon was known as 'the Planet Killer'. However, the LAAT/i was shot down, and Windu's force of clones were all dead. After burying them, he continued the mission.
Through lessons likely learned as a Jedi Padawan, Windu strove to complete his mission. Reaching a bridge, the Jedi Master encountered his first sign of Confederacy of Independent Systems droids. He fought his way through a large group of droids, defeating them all.
Upon reaching the 'Planet Killer', Windu fought and defeated two B2 super battle droids and then disabled the weapon by destroying its detonator.
As a result of the Planet Killer's failure, Count Dooku sped up plans for his own superweapon.
- Star Wars: The Comics Companion