The Jedi High Council tasked Jedi Master Sifo-Dyas with a mission to Felucia before the Invasion of Naboo. His assignment was to mediate a tribal dispute on the planet of Felucia. However, unbeknownst to the Council, Supreme Chancellor Finis Valorum had secretly dispatched Sifo-Dyas on a mission to Oba Diah to negotiate with the Pyke Syndicate. While en route from those negotiations to Felucia, Sifo-Dyas, along with the Chancellor's aide Silman, was assassinated by the Pykes at the behest of "Tyranus," who was secretly the former Jedi Count Dooku. Dooku, unknown to the Jedi Order, had embraced the dark side, becoming a Sith Lord and the apprentice of Dark Lord Darth Sidious, publicly the Naboo Senator Sheev Palpatine.
Dooku and Sidious orchestrated Sifo-Dyas' death to seize control of the clone army. Sifo-Dyas had secretly commissioned this army from the cloners of Kamino, a remote planet, having foreseen a coming war that would necessitate the Galactic Republic possessing a military force. Following the assassination, Dooku journeyed to Felucia with Sifo-Dyas' body, deceiving the tribal elders by presenting himself as another Jedi accompanying the still-living Sifo-Dyas. The Sith Lord then staged Sifo-Dyas' death during a fabricated conflict and had the body cremated.
The Jedi Council remained under the impression that Sifo-Dyas had died on Felucia until the final year of the Clone Wars. At that time, the wreckage of Sifo-Dyas' ship was discovered on the Oba Diah moon, containing his lightsaber. This discovery served as definitive proof that his demise could not have occurred on Felucia. Anakin Skywalker and Obi-Wan Kenobi were dispatched to interrogate the Pykes, ultimately uncovering the true circumstances surrounding Sifo-Dyas' death and the Sith's involvement.
The Star Wars: The Clone Wars episode "The Lost One" was the first time the Felucia mission was referenced.