A rookie officer is teamed with a hardened pro at the California Highway Patrol, though the newbie soon learns his partner is really an undercover Fed investigating a heist that may involve some crooked cops.
An FBI agent goes undercover in the California Highway Patrol as officer Frank "Ponch" Poncherello. Members of the CHP have been robbing cash delivery vehicles and his job is to uncover the perpetrators. At the CHP he is partnered with a 30-something rookie, Jon Baker. Baker is a former professional motorcycle rider with a list of ailments and personal problems who is lucky to be in the CHP. They are very different people and immediately clash.
The film begins with a getaway driver waiting for his crew in a Miami bank. Following a brief car chase, the driver reveals himself as Special Agent Castillo (Michael Peña) of the FBI. He then arrests the criminal crew who killed his former partner. During the arrest, Castillo fires his service weapon through his partner's, Special Agent Clay Allen's (Adam Brody), shoulder. He then proceeded to show a naked photo of the criminal's wife to prove Castillo's affair with her. Meanwhile, at the training center for the California Highway Patrol, Jon Baker (Dax Shepard) is a trainee who is awaiting his final exam to graduate. Failing a series of simple tests, he is placed at the desk of CHP Sergeant Gail Hernandez (Maya Rudolph) for a final interview and decision. Hernandez acknowledges his ability to "ride" a motorcycle better than the majority of the cadets she trained. She grants him probationary approval to graduate pending a performance review based on Citations, Arrests and Good overall evaluations from Superiors..
Jon Baker (Shepard) and Frank Ponch Poncherello (Peña) have just joined the California Highway Patrol (CHP) in Los Angeles, but for very different reasons. Baker is a beaten-up former pro motorbiker trying to put his life and marriage back together. Poncherello is a cocky undercover Federal agent investigating a multi-million dollar heist that may be an inside-job inside the CHP. The inexperienced rookie and the hardened pro are teamed together, but clash more than click, so kick-starting a real partnership is easier said than done. But with Baker's unique bike skills and Ponch's street savvy it might just work...if they don't drive each other crazy first.
- Jon Baker (Dax Shepard) is a former X-Games competitor who is now looking to become an officer of the California Highway Patrol. He gets himself amped up at home before heading off to begin his training.
Officer Castillo (Michael Pena) is a professional cop and womanizer. He is working undercover to take down a drug-dealing gang leader. Castillo has a particularly personal involvement in the case as the criminal murdered Castillo's partner not long ago. The crook holds Castillo's new partner Clay Allen (Adam Brody) at gunpoint, only for Castillo to shoot Allen for the bullet to go through and hit the criminal. Castillo then taunts him with nude pictures of his wife.
Somewhere on the highway, a gang of corrupt cops led by Raymond Kurtz (Vincent D'Onofrio) hijack an armored truck. Kurtz's son Reed (Justin Chatwin) pulls a woman out of her car so that the resulting explosion won't kill her. They blow the door off the truck, which cuts through the woman's car and hits a truck behind them, blowing it up. The gang steals from the truck and they make their escape.
Jon's training goes horribly. He places so far below in the results that even the handicapped trainees did better. He meets with Sgt. Gail Hernandez (Maya Rudolph) as she explains to him just how poorly he did. Jon then tells her that he is mainly doing this to save his marriage to his wife Karen (Kristen Bell) as she is considering leaving him. Gail relates since she has had troubles with her husband as well. Out of pity, she lets Jon join the squad.
Castillo is called to meet with his boss, Peterson (Isiah Whitlock, Jr.), who is not happy with how Castillo handled the recent case, with shooting Allen and the nude photos on his phone. Peterson reassigns him to go undercover with the CHP to take down the corrupt cops within their detail. Castillo is given the name "Francis Llewelyn Poncherello", or just his nickname "Ponch".
Ponch is sent to the CHP and is teamed up with Jon. They meet in the locker room awkwardly when Jon approaches Ponch while not wearing pants. Jon is very eager to start work and almost embarrasses himself and Ponch in front of the other officers. Jon meets Ava Perez (Rosa Salazar) and mistakenly thinks she's hitting on him while Ponch catches the eye of Lindsey Taylor (Jessica McNamee).
Around the city, Kurtz and his gang are striking again. Kurtz holds one of truck drivers at gunpoint as Officer Parish (Richard T. Jones) and his partner TJ are flying overhead in a helicopter. TJ is part of Kurtz's gang and is about to blow his cover, since the truck driver is TJ's boyfriend. TJ looks at Parish before jumping out of the helicopter to his death. Kurtz just flees.
Ponch and Jon begin their investigation by interviewing the woman who Reed pulled out of the car and witnessed the robbery. She mentions the leader being referred to as "L.T." Meanwhile, Jon is giving the woman a ticket and trying to ticket as many people as possible to meet his quota, still desperate to prove himself. The other officers can't help but laugh at Jon, including Kurtz, who is part of the CHP.
The guys visit TJ's wife to investigate his death. After not gathering much info, Jon tells Ponch that he noticed details about TJ's home, like how there were hardly any pictures of him with his wife or any sort of proof that he was a helicopter pilot or had any work with the CHP.
On the road, Jon pulls over a driver (Ed Begley, Jr.) for going too fast. The man tries to show Jon a gold widows card that gives him some kind of special privilege, but Jon isn't having it. Ponch pulls him away and lets the driver go because Jon is embarrassing them.
During their investigation, Ponch and Jon start to bond. Jon saves Ponch when he is nearly struck by a truck on the road, leading to his motorcycle getting wrecked. Jon makes Ponch return the favor by carrying him nude to the bathtub when Karen won't, because she's too busy with her not-so-secret lover Rick (Josh Duhamel). Ponch carries Jon and accidentally faceplants into Jon's groin as he trips.
When visiting TJ's wife again, the guys run into Parish, who is annoyed with the two for meddling in the case. Ponch mentions "L.T.", which Parish says stands for "lieutenant". The guys look through the database of active lieutenants in the area and come across Kurtz. They confront him at the gym but he tells them to fuck off since they have no proof that he has anything to do with the string of murders and robberies.
Kurtz and his gang pull off another heist in the streets, this time with Ponch and Jon on their tails. Ponch goes after Reed on his motorcycle after learning Reed is involved with handling unmarked bills with his associates. Some workers on the road try to stop the chaos by holding up a wire. Reed runs through the wire and is decapitated. Kurtz, now enraged, slams into Jon with his truck.
Ponch takes Jon to the hospital. The other officers, including Ava, go visit him. Jon waits for Karen to bring him home, but she never shows. Ponch is found by Peterson on his way out of the hospital and is confronted for botching the investigation with his antics and for having an attempted sexual encounter with the CHP Captain Lindel (Jane Kaczmaryk) (he was trying to have a sexy FaceTime with Lindsey). Ponch is fired.
Upon returning home, Jon finds out that Karen sold the house. Now alone and disgraced with Ponch, they find a new lead when they learn that Reed's full name is Raymond Reed Kurtz, Jr. and that Jon used to compete with him in sports.
Kurtz is getting ready for another heist with his accomplices, fellow CHP Officer Grieves (Ryan Hansen) and Lindsey. To make things worse, Kurtz kidnaps Karen and holds her hostage for Ponch and Jon to go rescue her. They enlist the help of the fellow CHP officers and get Lindel to officially instate Ponch to the CHP.
Ponch and Jon arrive at the warehouse to confront the villains. They get Karen untied but a shootout occurs where Ponch has three of his fingers shot off by Kurtz. Jon fights Grieves with their arm casts until Jon knocks Grieves out. Kurtz points his gun at the partners after Lindsey hands him another gun in front of Ponch and Jon. Kurtz shoots at Jon but Ponch dives in to save him. A bullet ricochets off Jon's arm (he had a metal plate put in there) and into Kurtz's head, killing him. Ava then tackles Lindsey to the ground and arrests her.
Ponch and Jon are taken in an ambulance to the hospital. Karen thanks Jon for saving her, but he's officially done with her. Ava rides in the ambulance with Jon and she kisses him. Ponch and the medic (Erik Estrada; the original Ponch) joke about Jon in Spanish as they ride away.
Two months later, Ponch and Jon are official partners in the CHP.