We see a teenage girl approaching a statue of a man labeled simply, “Author.” We then cut to the Author himself as he begins to share a story about his trip to The Grand Budapest Hotel many years ago. We see the younger version of the Author staying at the hotel years earlier. It is here he meets the owner of the establishment, Mr. Zero Moustafa, who tells the author he enjoys his writing and invites him to dinner to share his story of how he came to own the hotel.
At dinner, we flash back in time to 1932 when The Grand Budapest Hotel was flourishing. Gustave, the hotel’s meticulous and highly competent concierge, has a habit of sleeping with wealthy older guests of the hotel and is currently carrying on an affair with Madame D., a wealthy dowager countess in her 80s.
Shortly after Madame D.'s visit, Gustave learns that she has died. He and the new lobby boy, Zero who is the younger version of Mr. Moustafa, go to Madame D.s home in order to pay their respects. There they find her kids, extended family, and lawyer, Mr. Kovacs, waiting to hear the reading of the countess' will. Kovacs announces only one detail; that Madame has left Gustave a priceless painting, Boy With Apple. Madame D.’s son, Dmitri demands that Gustave be arrested. Gustave and Zero quickly leave, but not before they steal the painting off the wall and hide it for safekeeping at the hotel.
Once back at the Grand Budapest, Gustave is arrested for the murder of Madame D. While in prison he becomes friends with inmates and plans an escape. He has Zero place digging tools inside pastries that Zero's girlfriend, Agatha, bakes for him. Gustave and the other men are able to dig their way out and part ways. Zero and Gustave make their way back to the Grand Budapest with the help of the Society of the Crossed Keys, a group of concierges that call in favors to assist each other.
Gustave, Zero, and Agatha arrive back at the Grand Budapest to find it has been taken over by the country’s army; war has broken out. Agatha sneaks in to retrieve Boy With Apple, so they can sell it and hide away. Just as she comes out with the painting, however, Dmitri enters the hotel and spots her with the painting. Gustave and Zero go inside to save her as she tries to escape from Dmitri. Dmitri opens fire on them and a gun battle erupts involving all of the soldiers staying in the hotel. Agatha’s attempt to escape leaves her and Zero hanging from the balcony of one of the rooms before they fall into a car full of pastries, which break their fall.
Agatha discovers a note hidden on the back of the painting that states that if Madame D.’s death was caused by murder, she is leaving everything to Gustave. Gustave becomes one of the wealthiest men in the country, and the owner of The Grand Budapest Hotel. While journeying by train, he, Zero, and Agatha are stopped by the army’s death troops who tear up Zero’s identification papers (he is a refugee). Gustave begins to fight the men and is shot dead.
Zero is Gustave’s only heir to his fortune, and this is how he inherited his great wealth, but also the reason why he traded all of his commodities for The Grand Budapest, which is now a struggling property as it holds all the memories of his time with Gustave and his relationship to Agatha.
The Author then turns this story into a book, which the young girl from the beginning of the film loves. We see her sitting on a bench beside the statue of the Author as the film closes.
