Plessus Ghon was a Jedi Knight of the Old Republic, serving the Jedi Order when the Republic's stability was being threatened by a group calling themselves the Separatists. While the Republic faced off against the Separatist on a galaxy wide scale, individual sectors and planets were engulfed in conflicts as well, almost all a direct result of the activities of the Separatists. The Jedi were hard at work, with many members of the Order spread across the galaxy trying to contain the violence rampaging in some systems, and finding peaceful solutions between parties at odds.
Plessus Ghon was one of those Knights sent to help stop that violence. In Plessus' case, the planet was Kabal. Kabal was a planet located on the Sharlissian Trade Corridor, and with Republic taxation of the route, the Trade Federation was unable to continue food shipments to the planet due to the increased cost. After months without food, the people of Kabal, mainly the citizens of the city called Shoribus, took to the streets rioting and protesting against the lack of food. The rioters attacked government buildings and a number of people were killed including the Kabalian leader, Jan Dovu.
The Jedi sent a team of four Knights, Plessus Ghon, Ixian Rovieda, Nygreena Clo, and Renxis Dielle. Unfortunately, even Plessus and the task force of Knights were unable to quell the rioting, and were claimed by the violence. All four Jedi, Plessus, Ixian, Nygreena, and Renxis were killed in the riots, a fact later confirmed by the Jedi Council. The riots were finally stopped when food shipments arrived courtesy of Separatist leader Count Dooku, along with Separatist and anti-Republic propaganda. Plessus and the Jedi became one with the Force upholding their beliefs of protecting peace and justice in the galaxy, but unfortunately, the problem was just a facet of a much grander scale, too much for only four Knights to handle.