The rescue operation known as the Mission to Kashyyyk was undertaken by the elite Delta Squad commandos of the Republic and directly preceded the Battle of Kashyyyk. This mission was composed of multiple operations, beginning with Operation Furball, which aimed to liberate the Wookiee chieftain Tarfful. Next came Operation Intervene, designed to eliminate Separatist supplies and installations. Subsequently, Delta Squad's Operation Forest Fire focused on demolishing the Kachirho Bridge to halt the Separatist offensive. However, the success of all these efforts was jeopardized when a Recusant-class light destroyer commenced deploying numerous combatants. Delta Squad's final action on Kashyyyk, Operation Gauntlet, involved destroying the enemy ship by seizing control of several Wookiee dual missile turrets.
Etain Tur-Mukan, a Jedi General, and Boss led the commandos in an infiltration of a Trandoshan mercenary camp. The purpose of this operation was to free the Wookiee Chieftain Tarfful. The commandos were successful in their rescue of Tarfful, extracting him from the clutches of several of General Grievous's bodyguard droids. Furthermore, they acquired intelligence pertaining to the Confederacy's partnership with the Trandoshan mercenaries.
Delta Squad also discovered that the number of enemy forces on Kashyyyk was greater than initially estimated by the Republic High Command. Following this discovery, the squad proceeded to sabotage the Trandoshans' base on Kashyyyk, resulting in the destruction of two landing platforms. When the Confederacy launched a large-scale invasion of Kachirho, the Wookiee city built in the trees, Delta Squad was the only Grand Army of the Republic unit present on the planet capable of providing defensive support. Delta Squad undermined a bridge connecting the two sides of Kachirho, halting the Confederacy's advance. The commandos also secured essential munitions and ordnance depots for the Wookiees, which helped them to arm themselves adequately for the fight against the Confederacy.
The ultimate objective was the destruction of a Recusant-class light destroyer that was trying to deploy more battle droids to the planet's surface. After the cruiser was destroyed, Sev, the team's sniper, went missing and was presumed killed in action. However, orders directly from Grand Master Yoda compelled Delta Squad to abandon Sev. Delta Squad was then extracted and redeployed as the Republic invasion force arrived, at which point they joined the Battle of Kashyyyk.
According to Star Wars: Republic Commando, this mission took place 785 days, or approximately two years, after the Battle of Geonosis. However, Ryan Kaufman, a primary writer for Republic Commando, has clarified that this date was an error made during development. The mission was intended to occur in the days leading up to the Battle of Kashyyyk, as depicted in Star Wars: Episode III Revenge of the Sith, which is set in 19 BBY.