Ambush

"Ambush" is the first episode of the first season of Star Wars: The Clone Wars. It is the first episode of the series overall. It premiered on October 3, 2008.

Official Description
Jedi Master Yoda and three clone troopers -- Jek, Thire, and Rys -- must face off against Count Dooku's dreaded assassin Ventress and her massive droid army to prove the Jedi are strong enough to protect a strategic planet and forge a treaty for the Republic.