The initial episode of the Star Wars: The Clone Wars series, "Ambush," also marks the premiere of Season One. Prior to its debut on television, this episode was screened during the Television Critics Association press event on July 11, 2008, and subsequently at Dragon Con held in Atlanta, Georgia that September. "Ambush" was then broadcast on Cartoon Network on October 3, 2008. Although it holds the position of series opener, "Ambush" actually takes place as the fifth episode in the chronological order of events, following "Supply Lines" and preceding "Rising Malevolence," which is the first part of a trilogy.
Master Jedi Yoda embarks on a clandestine endeavor to establish a formal agreement with the monarch ruling the strategically vital system of Toydaria, only to have his vessel fall into an ambush orchestrated by Count Dooku. To demonstrate the Jedi Order's capability to safeguard the king and his subjects from the ravages of war, Yoda, accompanied by three Clone troopers, must confront Ventress, Count Dooku's fearsome assassin, and her expansive droid army.
Yoda, a Jedi Master, receives orders to journey to Rugosa, a moon composed of arid coral, with the mission of persuading King Katuunko to permit the Galactic Republic to establish a military installation within Toydarian territory. As Katuunko and his entourage await the arrival of the Jedi delegation, Asajj Ventress makes her entrance, presenting Katuunko with a holographic transmission from Count Dooku. Dooku's message aims to sway the king towards the Separatist cause by highlighting the Jedi's supposed inability to guarantee Toydaria's security.
In the space surrounding the Rugosa moon, two Banking clan frigates launch a surprise attack on Yoda's ship. Yoda, along with three clone troopers—Lieutenant Thire, Jek, and Rys—manage to evacuate to the moon's surface using an escape pod. As the Republic frigate retreats from the system, Asajj Ventress capitalizes on the opportunity, pointing to the fleeing vessel as evidence of the Republic's weakness.
Yoda establishes communication with Katuunko via hologram, informing the king of his landing in the vicinity. Ventress proposes a challenge: Should Yoda successfully evade her elite troops, Toydaria would be at liberty to align itself with the Republic. Conversely, should he fail and her droids emerge victorious, Toydaria would pledge its allegiance to the Separatists. Despite the king's reservations, Yoda accepts the challenge.
As Yoda and the clones advance toward the designated meeting point, a Separatist transport touches down nearby, unloading a full battalion of droids. The dense coral forest presents a significant obstacle, prompting the droid commander, designated 224, to instruct his forces to dismount from their tanks and proceed on foot. This tactical shift allows Yoda and the clones to execute ambushes against the droids in smaller, more manageable engagements. However, the clones' position is eventually pinpointed by larger enemy contingents, resulting in Lieutenant Thire sustaining an injury. Consequently, the clones are compelled to withdraw, accompanied by Master Yoda.
Yoda guides the clones to a concealed cave to recuperate. The clones, disheartened by their numerical disadvantage and dwindling ammunition, experience a dip in morale. In an effort to uplift their spirits, Yoda imparts his wisdom regarding their individual identities as individuals, notwithstanding their shared origin through cloning, and reassures them that they possess all the necessary attributes to triumph.
As a column of droids and tanks approaches, Master Yoda resolves to confront them single-handedly, instructing his clone troopers to remain hidden and assuring them that they will be signaled when their assistance is required. The enemy proves to be a minor obstacle for the Jedi Master, who skillfully cuts through their ranks, steadily reducing their numbers with his lightsaber. Enraged by this turn of events, Ventress dispatches ten droidekas to eliminate the Jedi. Suspecting that Master Yoda is too preoccupied to detect the approaching droids, Lieutenant Thire fires their last RPG at an overhanging bluff, triggering an avalanche of rocks that crushes the reinforcements and brings the combat to an end.
Impressed by the combined efforts of Yoda and the clones, Katuunko decides to align with the Republic, citing Ventress's act of deception as a key factor in his decision. Count Dooku orders Ventress to assassinate the king. Ventress incapacitates the king's guards and prepares to strike him down, but Master Yoda intervenes just in time, using the Force to siezes Ventress. Yoda demands Ventress' surrender, but Ventress triggers pre-planted explosives remotely, causing a landslide that allows her to escape in her solar sailer. King Katuunko presents his sword to Yoda, offering his allegiance to the Republic, as Republic gunships arrive to extract both parties.