Plot
Owen Browning, a young bank manager, and Parker McDermott, a yoga instructor, are about to get married. When Parker's estranged parents contact her to come to the wedding, Owen is excited that he will get to meet them, but she is concerned they can be overbearing.
Owen calls Neil and Margie, his difficult and anxious parents, to relay the good news about Parker's parents attending the wedding. They show their ignorance of Parker's profession as a yoga instructor, believing it involves a stripper pole, and rather than being happy about the news, they criticize Parker's parents for being absent in her life.
At the bank, Owen has to free an employee locked in the vault as the result of a prank. In doing so, he shows and talks about how state-of-the-art their bank's security system is. They point out their rival bank's vault security is considered the best in the state. Owen also points out all vaults have an emergency escape latch.
Out at dinner with his parents, they talk about the impending arrival of Parker's parents. Meanwhile, Owen talks with the storage space facility where they rent, as he's hoping to access photos of Parker for a wedding photo montage. His call inadvertently alerts Rehan, a crime boss, to their return.
The following night, Parker's parents scare Owen when they let themselves into the soon-to-be-married couple's home, while Parker is still out leading a yoga class. They insist Owen calls them Billy and Lilly. The next day, Owen takes a day off work to spend with the in-laws. They pick the agenda, so they go skydiving, get tattoos, and drink.
Within 12 hours, an infamous full-costumed pair of criminals called the "Ghost Bandits" hold up Owen's bank, with Owen, now hungover, in the building. Owen notices specific indicators such as the male's cologne, giving him flashbacks to the bar the night before. He also recalls security details he told Lilly, prompting him to believe that the robbers might be his future in-laws.
FBI special agent Roger Oldham questions Owen as the bank manager, with Billy and Lilly behind him. Not able to say anything, Parker insists they leave once Owen breaks out in tears. Oldham has dedicated most of his career chasing the Ghost Bandits and he's convinced they are behind the robbery. Trying to enlist his parents' help in outing Billy and Lilly, Owen tells them his suspicions. They do ask direct and inappropriate questions at dinner, but Billy and Lilly expertly redirect the conversation. Parker later asks Owen why he is acting strangely, and while he tells her of his theory, she believes it is crazy.
Owen follows his in-laws to Rehan's and hears Rehan threaten to kill Parker if they don't get her $5,000,000 more before the wedding. Oldham stops Owen on the highway, finds planted evidence in the trunk, and spills it on his in-laws. Oldham puts a wire on him, hoping to get Billy and Lilly to confess. Instead, Rehan shows up with her henchmen and takes Parker hostage as insurance. Disgusted, Owen joins forces with Billy and Lilly.
They first choose Victory Union Bank to rob, but after losing most of the cash they focus on the much bigger Atlas Reserve. Owen asks its manager, Phoebe, how he can better equip his bank, and she arrogantly shows him all of the safeguards. Just as the vault opens, Billy and Lilly create a diversion out front, while Owen locks himself in the vault and then uses the emergency escape latch to escape with the money.
At the ransom drop, Rehan is pleasantly surprised that Owen brought the money, but will kill them anyway. Owen miraculously guns them down as Billy and Lilly distract the cops, so Owen can sneak back into the vault with the money.
Finally as Billy and Lilly turn themselves in, agent Oldham lets them go briefly to Owen and Parker's wedding reception. During the credits, Owen slips a paperclip into a piece of cake for Billy and Lilly to use to get free of their handcuffs.
