The film opens as Bobby (Jacob Elordi) drives a severely wounded, possibly dead man, through the desert while nonchalantly discussing the Hoover Dam. Bobby pulls off the road and dumps the body from his car before driving off.A few weeks earlier, in the Summer of 1964, Jim's (Zachary Quinto) car breaks down while driving east on Route 66 through Death Valley, California. He brings it to a mechanic shop run Willard (Christopher Guyton) who is able to keep the car running for a steep price and off-handily mentions Jim's cargo. Before leaving the shop, Jim calls his wife and business partner Esther and suggests he take a detour to visit someone named Saul, but Esther chastises Jim, pointing out she put a lot of work into forming this plan to make-up for Jim's lack of work.While talking with Esther, Jim notices Bobby attempting to hitch a ride to Michigan and then antagonizing Willard. Jim offers Bobby a ride who accepts, telling Jim his car broke back in Death Valley.Bobby mentions that he is heading to Michigan to attend a homecoming with his girl, while Jim admits he picked up Bobby because he is running behind on a trip to Chicago and may need someone to help with driving to make up some time. While on the road, Jim and Bobby small talk but the conversation turns tense when Bobby reacts negatively to Jim asking about his discharge from the Air Force.The tension is broken when Bobby hears a noise coming from the back of the car. Jim pulls over and reveals he is transporting a chimpanzee named Spanky to Chicago. At first Bobby is put-off by Spanky, but after recognizing him as a celebrity chimp that frequents the talk shows, Bobby decides to continue with Jim.The three stay at a motel in Albuquerque, New Mexico for the night. Jim offers to get a room with two beds but Bobby plans to sleep in the car. Bobby offers to feed Spanky, but Jim turns down the offer due to safety concerns, much to the annoyance of Bobby.The proprietor of the motel, Hank (Troy Evans), warns Jim about the danger in the area and attempts to sell him a knife, though Jim only asks for a room. While heading to his room, Jim is called over to a different car by Bobby who then holds him at gunpoint. Jim pleads for his life and Bobby spares him, but not before beating him and stealing his wallet ring. He warns that if Jim calls the police Bobby will kill Spanky.In flashback, Bobby murders an Air Force pilot. Jim once again calls Esther and suggests going to Saul's but he does not mention Bobby or the stickup. The next morning Jim sees the car still there and checks on Spanky who seems to be doing well. Jim attempts to talk to Bobby about the previous night but a police cruise pulls up, frightening Bobby. Jim denies calling the police but Bobby forces him into the car and the two drive off.On the road again Jim offers to take Bobby all the way to Chicago and ensure he reaches his destination of South Haven, Michigan on time in exchange for his wallet and keys, though Bobby counteroffers with the possibility of him shooting Jim in the head and stealing everything.Arriving in Amarillo, Texas, Jim pulls off the road as he previously mentioned to Bobby. The two pull up to a trailer in the middle of the desert that is being used as residence and place of worship run by Saul, who turns out to be a Catholic priest. Saul (Patrick J. Adams) mocks Jim for being in the show business and being an ape trainer, believing that they both turned Jim away from Christ. Meanwhile, Jim questions Saul's effectiveness as a preacher in the middle of the desert, though Saul still offers Jim a drink.Jim brings up a previous loan he made to Saul, who is also Jim's brother-in-law, which Saul has not paid back in over two years. Jim is desperate for money after the network canceled their contract with Spanky and they have struggled to find other jobs. Spanky had recently developed health issues and this has driven Jim into debt. Saul belittles Jim who attempts to return the insults but Saul gets the best of Jim. Jim threatens to have Bobby take care of Saul but when Jim approaches Bobby with the idea, he instead chokes Jim and forces into the back of the car and into the cage with Spanky. However, after Saul makes another sarcastic comment towards Bobby. Jim hears a gunshot from the back of the car.Bobby pulls off to the side of the road and confronts Jim about feeling used and tries to force Jim to admit that he only picked up Bobby to use as muscle with Saul, though Jim denies it.In another flashback, we see Bobby taunt another captive, revealing to him that his father was a horribly abusive man. After Bobby finds a gun on the man, he accuses him of being a liar and shoots him in the head.Jim is now bound and gagged in the front seat and Bobby tells him that awhile back he became tired of people lying to him and decided if he ever catches someone lying to him he would kill them. Bobby warns Jim that if he finds out he is lying again or tries anything, he will kill him.Arriving in Tulsa, Oklahoma, Bobby decides he wants to go dancing. He and Jim get ready together and Jim lends Bobby some clothes to fit in better. The two arrive at Rodney's, the dance hall, but Bobby becomes frustrating when he finds out that the ballroom program has been changed to a rock n' roll program, lowing the chances that he'll be able to meet a girl and form a relationship. Jim encourages Bobby to just go talk to a girl and uses Spanky to break the ice with a group of girls for Bobby.The girls, Whitney (Alexandra Doke) and Amy (Nicolette Doke), are impressed with Spanky and Bobby attempts to flirt with them. Jim is horrified to learn that Bobby plans to sleep with the girls, ashamed to be part of Bobby's scheme. Bobby takes the girls back to a motel and begins flirting again. He begins to ask them how a man could win back the heart of an ex who he was still in love with but becomes volatile after he losing in gin.Meanwhile, Jim returns calls on potential jobs for Spanky, getting turned down on each one. Jim then calls Esther who reveals that Saul was not killed by Bobby and he told Esther everything. Jim ends the call after hearing screaming from Bobby's room. He rushes in and the two girls accuse Bobby of grabbing them and threatens to tell the authorities. Jim covers for Bobby telling the girls that Bobby is an up and coming actor who was in character for a role. He is able to calm the girls who eventually fall asleep in one of the beds.Jim and Bobby stay up and Bobby reveals that he wanted to talk to the girls about his ex, Bonnie, who left him and how he can win. her back. Jim suggests that Bobby should stop being so forceful, though Bobby insists he is a gentle person as he sneaks over to the asleep girls and begins to kiss one's bare legs and hike up her dress.The next morning Jim is severely hungover after staying up all night with a bottle of whiskey watching Bobby. While stopped at a convenience store in Missouri, Bobby has Jim steal medicine that he needs to calm his nerves, and Jim is surprised to find the act of stealing exciting. Bobby later notices an article about a slaying at a gas station and becomes nervous.While at a diner in St. Louis, Bobby tells Jim that he his hoping to make it to Michigan for Bonnie's birthday party, bringing her souvenirs from all the places he's now traveled to in hopes that it will show his potential to her. Jim encourages Bobby, telling him that he can do anything. Bobby reciprocates Jim's kindness by giving him back his wallet and ring. Jim tries to get Bobby to give him the gun as well, but stops after Bobby does not seem to like the idea. Jim leaves the diner but Bobby attacks the cook who was staring at him, stabbing him in the hand. The two flee into Illinois.Spanky has not eaten in three days so Jim forces Bobby to pullover so they can feed him. Bobby instructs and trains Bobby on how to feed Spanky. The two continue to bond as they drive through Illinois. Bobby decides to take a nap and Jim notices the gun setting on the dashboard.Jim and Bobby arrive in Chicago and prepare to go their separate ways but Bobby notices his gun is missing. He confronts Jim over it who admits that he threw the gun away while Bobby was sleeping. He tells Bobby that he doesn't need the gun and will be better off without it. Bobby attacks Jim and nearly chokes him to death before Jim is able to unlock Spanky's cage and Spanky pushes the door into Bobby knocking him down. While Bobby is on the ground, Jim returns his gun to him which he had not thrown out, reasoning that he tried to help Bobby. Bobby takes the gun and walks away.That night Jim decides to go find Bobby, eventually locating him walking and attempting to hitch a ride. Bobby threatens that he could kill Jim and Spanky, but Jim calls his bluff not believing he would after all they've been through. He lets Spanky out so Bobby can have a proper goodbye. Bobby gives Jim some money for food and lodging, while Jim gives Bobby the sweater he let him use in Tulsa. The two say goodbye and Bobby walks off.Jim arrives at a large estate with Spanky that is filled with various taxidermist animals on display. The mansion is owned by Suma (Ananyaa Shah) who criticizes Jim for using Spanky for performances but also refuses to call Spanky by his name. Jim raises the price of Spanky but Suma agrees to pay the raised price, planning to set Spanky free. However, when Suma attempts to grab Spanky he attacks her and Jim flees with her.Over a narration it is revealed that Bobby never made it to South Haven. He quickly returned to his previous ways and was eventually arrested after bragging about his murders. Jim and Spanky were able to find some success, eventually retiring from the show business industry.Bobby spent the rest of his life in prison.