Season 0 of Saiyuki premiered on 1999-04-23.

Season 1 of Saiyuki premiered on 2000-04-04.

Priest Genjo Sanzo and companions Cho Hakkai, Sha Gojyo, and Son Goku maintain their westward journey to stop the resurrection of the demon Gyoumao. As the reputation of the Sanzo Ikkou precedes them, they continue to fight demon assassins at every turn, but they must also deal with increasing tensions within their group in order to defeat a powerful enemy.

The Sanzo Ikkou continues its westward journey, on a mission to prevent a demonic resurrection. As Genjo Sanzo, Cho Hakkai, Sha Gojyo, and Son Goku fight their way to their goal, their path is fraught with internal strife. When they encounter a formidable pair of adversaries from the west, the cohesion of the group -- and the fate of the mission -- may be at stake.

Humans and yokai, science and magic... all exist side-by-side on a peaceful continent free of all order and regulation, widely known as "Shangri-La." The balance there was shattered when the Minus Wave caused all the yokai on the continent to rampage, an event known as the "Calamity." Continuing their journey west to stop Gyumaoh's resurrection experiments, the root of all the evil on the continent, the Three Aspects are finally drawing closer to India. But the closer they get, the more pronounced the influence of the Calamity becomes, and the more intense their battles become.

When the monstrous Gyumaoh was defeated by the war god Nataku Taishi and imprisoned in Houtou Castle, an era of peace began in the land of Togenkyo. Now, hundreds of years later, those seeking to resurrect Gyumaoh have unleashed a plague upon the world. The wave of negative power generated by his attempted resurrection has driven youkai to the brink of insanity. To save humanity from violent slaughter, Kanzeon Bosatsu sends Son Goku, Genjou Sanzou, Sha Gojyo, and Cho Hakkai to the west in order to prevent Gyumaoh from rising once again.