Charlie and his family board the flying Great Glass Elevator to return to the chocolate factory now that Willy Wonka has rewarded Charlie with its ownership. When Wonka attempts to bring the Elevator high enough to punch back into the factory, it accidentally goes into orbit. Wonka docks them instead at the empty Space Hotel ”U.S.A.”, which is coincidentally nearby, causing baffled officials back on Earth (including U.S. President Lancelot R. Gilligrass) to accuse the group of being foreign enemies. Wonka tricks them by loudly singing gibberish, pretending to be an alien, but is interrupted by the discovery that the hotel contains actual dangerous, shape-changing aliens known as Vermicious Knids. The band escapes back into orbit in the Elevator.

Once they leave, the President allows the Commuter Capsule, carrying astronauts and Space Hotel staff, to dock with the Space Hotel. Upon entry, the Knids devour several staff members, prompting an immediate evacuation. The Elevator, having circled around the Earth, braves the swarm of Knids to tow the damaged Capsule out of danger. During a last attempt by the Knids to tow the craft away themselves, they are incinerated by Earth's atmosphere. The Elevator crew releases the Commuter Capsule and crashes through Wonka's factory roof. Upon landing, Wonka is greeted warmly by the Oompa-Loompas, who were concerned about his prolonged absence from the factory.

Back in the factory, Charlie's three bedridden grandparents refuse to budge. Wonka offers them rejuvenation pills called ”Wonka-Vite”, but they overdose, resulting in two becoming babies and Georgina vanishing, having become -2 years old. Charlie and Wonka ride the Elevator to ”Minusland” to find her, and Wonka sprays her with the opposite of Wonka-Vite – ”Vita-Wonk” – to age her again. Upon returning, they discover that Georgina is now 358 years old. Wonka gives her another calculated dose of Wonka-Vite to return her to normal, then gives each of the babies enough Vita-Wonk to restore them, too.

Immediately afterwards, Wonka gets a letter from President Gilligrass, thanking everyone for their heroic efforts and inviting them to the White House. The group celebrates, and the prospect is enough to finally bring the three grandparents out of bed to join in.