The book consists of 100 chapters. The first seven deal with the tale of Monkey's revolt against heaven. A stone monkey is born on the Eastern Continent, becomes the monkey king, and travels west to attain immortality. He is taught by a Taoist master who warns him never to reveal how it was that he attained his powers, and prophesises that in 500 years he will be struck down by heaven lest he finds a way to escape his fate. None of this ever comes up again, because an overarching theme of the book is a contempt for continuity.
This takes us to the main section of the book. The Buddhist priest Sanzang is tasked by the Bodhisattva Guanyin to travel to distant India (36,000 miles, or 1.5 times around the world) to worship the Buddha and retrieve some Buddhist scriptures, as a test of his faith. The "divinity testing mortals" trope is stupid in the best of times, but unfortunately this is not the best of times. This is Journey to the West. As such, in order to assists Sanzang on this "test" he is allotted three immortal companions -- Monkey, Pig and Friar Sand -- a dragon horse, an arsenal of magical artifacts, and some two dozen attendant gods. When that proves insufficient, as it often does, the Jade Emperor and his heavenly hosts, Lord Lao Zi, the Buddha from the Western Heaven, and Guanyin herself turn up to rescue him from the predicaments he winds up in. To make things worse, it is revealed that some or all of the obstacles in his path have, in fact, been placed there by Guanyin. So in other words this "test" of Sanzang's faith involves of Guanyin setting up problems, and then solving them herself. How this is any different from bringing the scriptures over on her own is anyone's guess.
This is just as well for the sake of the story, however, as Sanzang is completely useless, and would fail any test set before him when given the chance. Not only do his disciples save him from every peril he, seemingly intentionally, blunders into during his quest, even the banal details like begging for food and carrying the luggage is left to the immortals, while Sanzang sits on his horse doing nothing. I can accept that, being a mortal, he does not have any magical powers himself and has to rely on his disciples to do the heavy lifting for him, but it's not like he has any redeeming features to make up for it. He is an utter moron, and completely incapable of learning, falling for the same tricks again and again. He is a coward, and falls of his horse whenever someone looks at him funny (not to mention the time he spent an hour gathering up the courage to talk to some women. "Primal masculinity" indeed). And, despite the book going on about his virtue, in his interactions with other characters he frequently comes across as an asshole.
The adventures themselves are dull and repetitive. They follow the formula of, the pilgrims come to a mountain/river, Monkey warns of a demon, Sanzang abuses Monkey, demon captures Sanzang and tries to eat/mate with him (but doesn't actually, even if given more than enough time), Monkey either whacks the demon on the head with a cudgel, or goes and gets another divinity to whack the demon on the head with a cudgel. Repeat 81 times. In the afterword the translator mentions that we cannot reasonably expect any suspense from the stories because the pilgrims triumph in the end, but it's a lot worse than that -- we know that Arnie will eventually shoot the badguy, but at the same time there is risk involved: if he gets shot in the head he would die. Not Monkey. Monkey is indestructible, as he points out and demonstrates on many an occasion. The problem is no that we know in advance that Monkey won't fail, but rather that failure is impossible. Monkey can't die, and even if Sanzang were to die then Monkey has demonstrated that he is perfectly capable of bringing the dead back to life. His powers are so vast, that there is absolutely nothing that could stop him.
Which brings us to the next problem, the magic overload. Monkey's powers are so enormous that the author simply cannot come up with any credible challenges to him. At the end of the day, he could simply fly Sanzang to the Western Heaven and be done with it (the author does attempt to lampshade this -- "Mortals are heavier than mountains" -- only problem is, Monkey is perfectly capable of transporting Sanzang and other mortals by air when it suits him, as are other monsters. Oh, and, Monkey is perfectly capable of lifting mountains). The translator notes that the appeal of the stories is the cleverness of Monkey's solution to them, but it's hard to appreciate this cleverness when Monkey's choice of strategy is dictated not by the challenge he faced, but by the author's decision to write about one ploy or another. In one adventure Monkey knocks down the gates of a monster's abode. In another he turns into an insect and flies through the gap. In another he stands outside helpless. Why? Are these gates unbreakable? Are there no cracks to squeeze through? No, no reason is given. We can only assume the gates are the same as always. It's just that the author decided that this particular adventure needs a McGuffin of some sort. Or the intervention of another deity. Or, just, that the book is somehow not long enough as it is.
Of course, this makes it difficult to interpret the situations in which Monkey actually does find himself powerless to defeat one monster or other. Monkey made war on heaven, and only just lost. And now some animal spirit on the way to India is stronger than Monkey? Just how tenuous is the Jade Emperor's hold on authority? Why does none of these monsters depose him and be done with it?
The most interesting bit of the book is the translator's note at the end, which details some of the book's history, confirming the reader's suspicion that it is most likely a collection of independent stories than a cohesive whole. However, unlike the translator I do not believe that this lets the book of the hook for being terrible. Good stories need no excuses, they can stand against the best of novels on their own strengths. This is simply not a good collection of stories.