In 1971, journalist Raoul Duke and his attorney, Dr. Gonzo, are driving from LA to Las Vegas to cover the Mint 400 Motorcycle race. Along the way, they pick up a hitchhiker, and Duke explains the preparation for the trip, including gathering several drugs and renting the "Great Red Shark". Shortly after explaining, the two scare off the hitchhiker, and then take a large dose of LSD and finish the drive to Vegas.
The two arrive in the lobby of the Mint Hotel, while still under the influence of LSD. Duke has bizarre hallucinations and acts strangely, culminating in him perceiving everyone in the bar to be giant lizards. Gonzo, who is able to keep a level head throughout all of this, signs the two in with press credentials, and brings Duke up to their hotel room. They later leave to get an early look at the Mint Gun Club, where the race will be held. While there, Duke meets Lacerda, a photographer assigned to work with them.
The next day, Duke and Gonzo go to the bar at the gun club and wait for the race to start. Once it starts, Duke is unable to tell what is going on, and goes on a side-by-side ride with Lacerda, to capture photos. Eventually, Duke gives up and leaves.
Later that night, Duke and Gonzo are driving around Vegas intoxicated. After struggling to find parking, they go to the Desert Inn to see a Debbie Reynolds performance. The pair get kicked out of the show for smoking marijuana. They then huff some ether and wander around the Circus Circus, in a drunken stupor. While in the Circus Circus, Gonzo starts to feel the effects of the mescaline pills that he took earlier, and the two leave. Back in the hotel room, Gonzo keeps getting worse. When Duke eventually calms him down, he reminisces about the 1960s, and goes to sleep.
He wakes up the next morning and finds that Gonzo is gone and there is a pile of room service receipts. Unable to pay, he flees, hoping to make a quick drive back to Los Angeles. While driving along in an extremely paranoid state, Duke eventually calls Gonzo, and finds that he was supposed to check into the Flamingo Hotel and cover a national police meeting on drug use.
After Duke finishes checking into the hotel, he is attacked by a teenage girl named Lucy. He then learns that Gonzo gave her LSD to "help her out" only to find that she is a devout Christian and has never even used alcohol. The two give her more LSD, and then drop her off at a different hotel, hoping she will not remember them. However, when they get back to the hotel room, they find that Lucy has left them a message, and is asking Gonzo for help. Gonzo manages to trick her into thinking that Duke drugged both of them, and that Gonzo is now being arrested, advising her to hide. Afterwards, Gonzo advises Duke to take adrenochrome. When Duke takes it, he experiences nightmarish hallucinations, before eventually falling asleep.
The next day, they attend the drug convention, where they observe a comically out of touch presentation by a police "drug expert". Later, the two drive in Las Vegas, and encounter a family from Oklahoma, whom Gonzo aggressively tries to sell heroin to. Afterwards, they stop at a diner in North Las Vegas, where Gonzo makes a provocative and offensive gesture to the waitress, leading to a confrontation.
Next morning, the two rush to the airport and upon realizing they are about to miss a flight to L.A., Duke drives onto the runway area of the airport, drops Gonzo off and escapes through a break in a fence. After the departure of his lawyer, Duke spends the remaining days in his hotel suite recounting memories from Aspen, and attempting to purchase an ape. Duke was sadly denied the ape after the owner discovered it was house trained. After a while, Duke himself boards a plane to Denver. The book ends with Duke purchasing Amyl Nitrite from the airport pharmacy, and consuming them in front of the petrified pharmacist.[9]
