The innocent Candide, an illegitimate poor relation in a noble family, has grown up in the baronial castle and come under the influence of the family tutor Dr Pangloss, who teaches him alongside Cunégonde and Maximilian, the children of the house, and the fun-loving maid Paquette. Pangloss has persuaded his pupils that “all is for the best in this best of all possible worlds”, with the result that Candide has a naïve faith in human nature. This is put to the test when he is thrown out of the house for daring to ask to marry Cunégonde, with whom he has fallen in love. He immediately finds himself press-ganged into an invading foreign army and caught up in a gruesome battle, in which all his relations, including Cunégonde and Maximilian, have ostensibly been slaughtered.
Forced to go travelling, Candide reaches Lisbon with the help of a kindly Anabaptist and meets Pangloss, who has survived the battle but is suffering from the syphilis he contracted from Paquette. They are caught up in the devastating Lisbon earthquake and then witness an auto-da-fé, organised by the Inquisition to burn heretics. Denounced as heretics themselves, they are sentenced to be flogged and hanged respectively. Candide survives his flogging and goes on his travels again.
Cunégonde has not in fact died and is now a high-class courtesan, kept [and shared] by the Cardinal Archbishop and a Jewish banker. She reflects on the pros and cons of her position before being found by Candide, who is overjoyed at being reunited with her. After he has killed both her influential lovers, the happy pair have no choice but to take the advice of Cunégonde’s new friend, an Old Lady, and flee the country.
The three runaways reach the Spanish port of Cadiz, where the Old Lady tells Candide and Cunégonde of her past adventures, which have resulted in her now having only one buttock. She advises them to adapt to all new circumstances, but before they have time to become assimilated into Spanish culture, they meet Cacambo, a servant of mixed race, who introduces them to a Sea-Captain. The Captain thinks that Candide shows potential as a swordsman and offers to take him to South America to fight for the Jesuits against protestant missionaries. With Cacambo now in their service, Candide, Cunégonde and the Old Lady set off for the New World.
The lecherous Governor is inspecting a new shipment of slave-girls. Among them are Paquette … and Maximilian, who has also survived and been forced to dress as a woman by his previous owner. He is snapped up by a more than friendly Jesuit and the Governor falls for Cunégonde, who plays for time by insisting on marriage before sex. Candide has no choice but to leave Cunégonde in the Governor’s clutches, because an arrest warrant for his murders has pursued him from Europe.
With Cacambo’s help, Candide reaches Jesuit headquarters and is astonished to discover that Paquette and Maximilian have joined the order, the latter having been promoted to Father Provincial. Maximilian and Candide quarrel again over Candide’s desire to marry Cunégonde and Candide stabs his old classmate. Once more a fugitive from justice, he has more adventures, including a spell in the earthly paradise Eldorado which leaves him very rich and therefore an easy victim for the unscrupulous Dutchman Vanderdendur, who sells him an unseaworthy ship to take him back to Europe. The ship sinks, killing Candide’s new friend Martin, a complete pessimist poles apart from Pangloss. Candide is saved though and makes the acquaintance of five dethroned kings.
This turns out to be a final destination for Candide, Pangloss [whose hanging did not prove fatal], Maximilian [now Chief of Police], Paquette [once again a prostitute] and Cunégonde and the Old Lady, who are employed to ensnare clients in an unsavoury casino. Candide is appalled and disillusioned by Cunégonde’s fate, but decides to make the most of the rest of his life by marrying her anyway and cultivating his garden.