The Sanzo- Ikkou were in a cabin having a holiday. It was a peaceful place with the lake and woods nearby. And why were they having a holiday?

You see, Gyokumen Koushu had died in cosmetic surgery, Rasetsu- nyo had awoken, and Gyumaou revived the moment Gyokumen Koushu died. It turned out the Minus Wave had been caused by Gyokumen Koushu's research team when they were trying to find a ' forever beautiful' pill for their mistress who of course needed it, wanted it badly so she didn't give a crap about the effects. So anyway, Gyumaou turned out to be a caring father.

So the Journey to the West was technically over. Gyumaou was not a threat- he had lost his memory from being in a coma for too long.

As a 'reward', Kanzeon Bosatsu gave them a holiday at the cabin. (more likely she was still interested in the 4 of them.)