It was a time of chaos, when Heaven and Earth were as one, and humans and demons (the youkai) lived together in peace. The foundations of civilization and religion were raised and reinforced in this land of Togenkyo, the paradise known as Shangri-la. But now a great evil threatens harmony in this great land. Far to the West, in India, someone is attempting to resurrect the youkai lord Gyumaoh by mixing human science with youkai magic. This forbidden practice has created a Minus Wave of negative energy that is spreading across Shangri-la, poisoning the souls of the youkai and turning them into mindless monsters. The only hope lies in four legendary heroes: Genjyo Sanzo (a high priest with low morals), Son Goku (the hungry and mischievous Monkey King, just released from 500 years imprisonment), Sha Gojyo (a water sprite with an addiction for good smokes and bad women, and Cho Hakkai (the legendary demon slayer, with his transforming dragon Hakuryu). To save Shangri-la, these unlikely companions, united by fate, must travel together-- into the west!