Mountain Girl is almost eight months pregnant when she receives a package in the mail from Mexico. It contains an audiotape that Kesey made for her, but the entire thing is inaudible. She can only discern that he "was in the jungle somewhere and paranoid as hell and smoking a lot of grass." They make the decision to take the bus to Mexico and to meet up with Kesey. The "heat" is turning up in California and the press runs more stories about the Watts Acid Test. First, however, Mountain Girl has to go on trial for possession of marijuana from the rooftop bust that started the Pranksters' legal trouble.
The trial is a bit of a farce. Mountain Girl and Hassler show up wearing strange clothes, and suggest that her problems are all Kesey's fault. Mountain Girl gets off with only a $250 fine, and the group immediately heads to Mexico. The trip down is a hard one. The bus breaks down every twenty miles, and the Mexican landscape sends off "bad vibrations." They find out that after the American newspapers ran stories about Kesey's faked suicide, the Mexican authorities began to look for him. Kesey's paranoia, however, motivated him to escape back to Mazatlan before they could find him. He now has a new identity and a fake ID.
When the Pranksters arrive in Mazatlan they are the talk of the town. All of the locals call them "Diablos" (devils) because of their Day-Glo colors and crazy outfits. No one is quite sure what to make of them. Finally Kesey shows up, looking much older, and the Pranksters feel that their fortunes are turning and that the great party can start again. Even as the Pranksters are beginning to establish a new routine in Mexico, the locals are becoming increasingly wary of them. Just as the "crazies" roll into town, so does a red tide, a biological poisoning of the ocean caused by plankton. The red tide kills all of the fish, and has a devastating economic effect on the village. Although everyone knows the red tide is a natural biological phenomenon, they can't help but associate its arrival with the arrival of these foreign devils and their crazy Day-Glo suits.
Eventually, the Pranksters choose to settle in the village of Manzanillo because it is out in the middle of nowhere: hard to find and hard to get to. However, the conditions ("can't git out in the daytime and do anything because of the heat; can't git out at night because of the mosquitoes") begin to drive them all a little crazy. They can do nothing but wait for telegrams from Kesey's lawyers in the U.S. as they try to work out a deal to get them back home. But so far, no good news is coming from the North.
They only have a few books to keep them company, one of which is the Bible. They begin to read the Bible and "linger" over it, and soon all the Pranksters begin to re-imagine themselves as biblical figures. Kesey is Esau, and they each take on a character from the book of Genesis. It is "3,000 years ago; for there is no time in this place; only an eternal now stretching on infinitely over the entire world..." The days continue to roll by without much happening, and they all plan for Mountain Girl to marry one of the Pranksters, George Walker. She had wanted to be legally married by the time the baby arrived, but of course she can't marry Kesey, though Kesey, his wife Faye, Mountain Girl, and Black Maria are all living together in a small shack in Manzanillo. Mountain Girl goes through with the wedding, and has her baby in a local hospital.
Slowly the Pranksters' spirits begin to pick back up. Hagen buys a huge turtle, and they paint a Day-Glo skull and crossbones on its shell and set it free. Sandy returns, as does Cassady, who carries a four-pound hammer that he constantly throws up in the air and catches. Then Bob Stone, from Perry Lane, comes to town to write a story on Kesey for Esquire. Stone and Kesey take off on a drug binge road trip in which they take massive amounts of speed and acid and have wonderful hallucinations in the Mexican desert.
Kesey begins to see the Pranksters' time in terms of Nietzschean ideas of the superman. Nietzsche, Kesey thinks, was actually an acidhead, and some of Nietzsche's thoughts begin to sound like the same ones that Kesey himself has when on drugs. The idea of the eternal return - that all life is always happening and the point is simply to go with it - seems to make perfect sense to Kesey, and he realizes now that the great goal of the Pranksters is to shoot through time and become superheroes.
When things start to go wrong for the Pranksters in the U.S., they all decide to head to Mexico to meet up with Kesey. They even pull a prank on the lawyers and judges at Mountain Girl's trial, promising to take care of her. In reality, Mountain Girl simply wants to leave with them and continue on their journey. Once again, the Pranksters take advantage of the protective nature of the legal system.
Like previous counter-cultural generations, the Pranksters see Mexico as a land of the "real," full of real people and real experiences, where the law is lax and people can do as they please. In Mexico, however, economic and social realities are more apparent to the Pranksters than they were in places such as Watts. In Watts, the bourgeois culture that the Pranksters were used to was always just right across town - they could return to the comforts of money and privilege whenever they wanted - but in Mexico, they are surrounded by the realities of poverty. Mexico is both literally and figuratively a desert, and offers them no safe haven where they can simply be Pranksters.
Back in the U.S. things are no better, as evidenced by the bad news that arrives daily via telegram. Several of the former Pranksters have been killed or seriously injured, and the money for lawyers and legal help is running low. Much like the biblical characters they compare themselves to, the Pranksters are now nomadic desert wanders with no real home and no real family.
Soon, however, Mountain Girl gives birth to a new baby, a new Prankster, and this signals a kind of rebirth for the group as well. Slowly they begin to regain some of their Prankster charisma, and when Bob Stone, a writer and old friend, comes to do a story on Kesey, he brings new hope for fun (as well as a batch of drugs). Kesey and Stone race across the desert, high on drugs, and Kesey begins to develop a new vision for the way things could be. He begins to compare his own philosophy to that of Nietzsche - though of course Nietzsche went mad and died alone and neglected. Regardless, Kesey thinks that his experiences might be the ultimate expression of the ideas that Nietzsche developed a hundred years ago. With these new ideas, Kesey envisions a way "beyond acid" that might just be able to take him and the Pranksters back home.