6x10 - Star Wars: The Clone Wars

A Jedi mission finds a lightsaber belonging to the long-dead Master Sifo-Dyas, prompting Yoda, Obi-Wan Kenobi, and Anakin Skywalker to begin an investigation into his decade-old disappearance. This sparks Darth Sidious to order Darth Tyranus to clean up any loose ends that may lead the Jedi to discover the truth of the Sith conspiracy.