A New York cop and his wife go on a European vacation to reinvigorate the spark in their marriage, but end up getting framed and on the run for the death of an elderly billionaire.
Nick Spitz is a New York police officer and his wife Audrey is a hairdresser. Audrey wants to go to Europe as Nick promised them, but with their 15th wedding anniversary coming up, she thinks they will never go. She confronts him on this and he lies that he has booked the trip for the celebration. Due to that, he quickly books the trip. On the plane, Audrey meets billionaire Charles Cavendish who invites the couple to join him on his family’s yacht for a party. Nick reluctantly agrees to it.
On the yacht, Nick and Audrey meet Cavendish’s ex-fiancée Suzi, his cousin Tobey, actress Grace Ballard, Colonel Ulenga, his bodyguard Sergei, the maharaja Vikram, race car driver Juan Carlos, and finally Malcolm Quince, Cavendish’s uncle, the owner of the boat, and host of the party. Quince announces that Suzi (his current fiancée much to Cavendish’s displeasure) is the only one to make the will believing the others to want him just for money. Before he can sign the will, the lights go out and when they come back on, Quince is found dead stabbed by his own dagger.
Nick (who has faked being a detective for Audrey’s sake) orders the room be locked and the guests return to their rooms. Later that night, the guests find Tobey dead from an apparent suicide. Upon arriving in Monte Carlo, the guest are questioned by Inspector Laurent Delacroix who believes Nick and Audrey are guilty of the murders and later orders a manhunt on them. At the Monaco Grand Prix, Nick and Audrey question the guests and that night, Sergei summons them to his room where he reveals Quince had another child who apparently died. When someone knocks on the door, the couple hide and when they come out, they find Sergei has been murdered. They flee and Audrey finds out Nick is not a detective and lied about booking the trip in advance. She is furious and leaves with Cavendish.
Nick follows Suzi to a library where he finds Audrey who reveals Cavendish is in the building as well. They realize Cavendish and Suzi are secretly in love and assume they are the culprits. A hidden gunman begins shooting and the couple flee where they are met by Juan Carlos and confronted by Suzi who is then killed by a dart. Nick injures the killer who gets away. Nick and Audrey then go to Quince’s mansion to confront Cavendish on the murders, but find him dead from a poisoning.
The couple summon Delacroix and the remaining guests (Ulenga, Grace, Vikram, and Juan Carlos). They all have alibis remaining they were two murderers. The couple deduce that Grace is the murderer who had help from Tobey, then killed him. Grace reveals that she is the child that “died” and that Quince’s money truly belongs to her. She denies being the killer, but Nick proves it and she is arrested. While celebrating, Nick and Audrey learn that she had another alibi meaning that there is another killer. They realize that Juan Carlos is the other killer wanting revenge against Quince who he blames for his father’s death. Juan Carlos kidnaps Delacroix causing Nick and Audrey to engage him in a car chase, but they are able to get the car to crash rescuing Delacroix. Juan Carlos then holds them all at gunpoint, but he is then killed by a speeding bus.
Delacroix thanks the couple and offers to help get Nick elected as detective. As a thanks, Delacroix treats the couple to a train ride on the Orient Express.
NYPD Officer Nick Spitz (Adam Sandler) has recently failed his detective exam, but doesn’t want to tell his hairdresser wife Audrey (Jennifer Aniston). After a dinner for their fifteenth anniversary, Audrey confronts Nick about how despite his promises after they got married they never went to Europe. Nick is an extreme cheapskate who never does anything nice for Audrey. Nick panics and says he was planning to surprise her, and the two head off to Europe. During the flight, Audrey meets Charles Cavendish (Luke Evans), and the two strike up a conversation. Charles’s fiance has recently left him and married his uncle. He’s attending their yacht party and invites the Spitz’s to join them. When Nick finds out, he doesn’t want to go, but Audrey convinces him the fancy yacht will be much nicer than their low budget plans.
On the yacht, they meet Charles’s ex-fiance Suzi Nakamura (Shioli Kutsuna), cousin Tobey Quince (David Walliams), and actress Grace Ballard (Gemma Arterton), and racecar driver Juan Carlos Rivera (Luis Gerardo Mendez), and Maharajah Vikram Govindan (Adeel Akhtar). Audrey is creeped out by Colonel Charles Ulenga (John Kani), Charles’s uncle’s old friend, and his bodyguard, Sergei Radjenko (Olafur Darri Olafsson). Charles’s uncle, Malcolm Quince (Terrence Stamp), arrives to thank everyone for celebrating his engagement. He notes they are all in his will, until now – he calls them all leeches who deserve nothing. He says he’s drafted a new will leaving everything to Suzi. Just before he signs the new will, the power goes out – a gunshot sounds, screams ring out – and when the lights return, Malcolm has been stabbed through the chest and is dead.
Audrey identifies Nick as a detective, and so everyone turns to him for guidance. He orders everyone back to their rooms until the yacht reaches land. Nick thinks the case is open and shut, Maclolm’s son Tobey, but Audrey says its too obvious – and a gunshot rings out. They find Tobey dead, gunshot wound to the head. The next morning, Inspector Laurent Delacroix (Dany Boon) arrives and questions everyone. Every guest says the strangest thing about the evening was the random Americans there. Delacroix tells the Spitzes he suspects them of being the killers.
Once the ship docks, the couple are determined to prove they aren’t the killers, and begin chatting up the various guests looking for clues. One suspect is Juan Carlos, whose father died because of Malcolm. Nick centers on Charles, but Audrey, who likes Charles, just thinks Nick is jealous of him. That night, they get a note inviting them to another room – where they find Sergei with a gun, who orders them to listen. He tells them that years ago, Quince stole the Colonel’s girlfriend – and that they had a child who died in childbirth. He says that the Colonel asked him how to kill Quince. When someone knocks on the door, the couple hides – and when they come out, Sergei has been murdered. They flee from the killer out a window, climbing across the hotel ledge, and end up hiding in Grace’s room where they discover she is sleeping with Vikram.
Nick and Audrey see Delacroix on TV calling them the prime suspects and that they are wanted – and that Nick lied about being a detective. The two get into a fight and Audrey realizes he lied about planning the trip in advance. Furious, she leaves with Charles. When Audrey discovers Japanese allergy medicine in the car, she realizes Charles is meeting with Suzi. She follows him and runs into Nick, and the two deduce that Charles and Suzi did it together. Someone begins shooting at them and they flee. They find Juan Carlos who takes them to Suzi – she holds them at gunpoint but is then shot with a poisoned dart by someone in a mask. Nick and Juan Carlos chase the assailant but he gets away.
Audrey and Nick head to Charles’s mansion to confront him, but find him poisoned to death. They panic but huddle up to figure it out. The remaining suspects and Dellacroix meet them at the mansion, where they deduce that Grace is Malcolm’s long-lost child who didn’t die as they were told. She convinced Tobey to kill Malcolm, then killed Tobey – she tried to kill Nick and Audrey once they became suspicious, and killed Charles because he loved Suzi and not her. Grace denies everything, but Audrey finds one final clue that proves it’s Grace, who pulls a gun and takes Audrey hostage, but Nick shoots Grace in the shoulder, and she’s arrested. Afterwards, Vikram points out that Grace was with him when Sergei was shot, and Nick and Audrey realize Juan Carlos is the other killer and has been faking his inability to speak English. He did it for revenge for his family. He takes Dellacroix hostage at gunpoint and steals a police car. The Spitzes take a ferrari and chase after, crashing Juan Carlos and rescuing the detective. Juan Carlos comes after them one more time and is hit by Nick and Audrey’s original tour bus.
Dellacroix thanks them tells Nick he’ll reach out to help make Nick detective. As a thank you, he gifts them a scenic train ride on the Orient Express.