In the mid-fourteenth century, Boccaccio seeks his true love, the recently widowed Fiametta (Joan Fontaine), and finds that she has fled Florence, plague-ridden and being sacked by an invading army, for a villa in the countryside with several female companions. When he shows up on her doorstep, Fiametta does not want to invite him to stay, but her friends, bored and lacking male companionship, override her objections. To entertain the ladies (and further his courtship of Fiametta), Boccaccio tells stories of the pursuit of love.
Bartolomea (Fontaine) is frustrated by her marriage to the wealthy, much older Ricciardo (Godfrey Tearle). The latter's strong belief in astrology dictates how they live. One day, the stars are favorable for fishing. However, a pirate ship appears suddenly and captures the ladies. The captain, Paganino (Jourdan), inspects his prisoners and releases all but Bartolomea. He sends her husband a demand for 50,000 gold florins ransom to be paid at Majorca. By the time Ricciardo shows up however, Bartolomea has fallen in love with the pirate. She denies knowing Ricciardo and, when he is unable to answer a simple question (the color of her eyes in the dark), Paganino's friend, the larcenous Governor of Majorca (Eliot Makeham), orders Ricciardo to pay a fine for his lies: the sum of 50,000 florins. Paganino and Bartolomea get married and he promises to give up pirating.
Fiametta is not amused by the "moral" of the story, but the others beg Boccaccio for another. Instead, Fiametta decides to recount a more uplifting tale, to her friends' disappointment.
Giulio (Jourdan) goads Bernabo (Tearle) into betting on the virtue of his wife Ginevra (Fontaine). Giulio wagers 1000 florins against Bernabo's 5000 that he can seduce Ginevra within a month. However, Giulio merely bribes the woman's maid Nerina (Binnie Barnes) into letting him hide in her mistress's bedchamber. Later, while Ginevra sleeps, he steals a locket with Bernabo's likeness in it and cuts off a lock of her hair, noticing as he does so a birthmark on her shoulder. When Giulio provides all three as "proof", Bernabo pays up. He then recruits two assassins to do away with his wife. The killers are discomfited by Ginevra's lack of fear and let her go.
She disguises herself as a man and becomes a sailor on a merchant ship. A potential customer, the Sultan (Meinhart Maur), becomes fascinated by Ginevra's pet talking parrot and agrees to buy the merchant's wares if he can also have the bird. Since the parrot will only speak for Ginevra, she agrees to enter the Sultan's service.
Then one day, she spots her locket in a marketplace stall manned by Giulio. Still in disguise, she coaxes the story out of him and finally learns why her husband wanted her dead. She then has the Sultan invite both Giulio and Bernabo (now working for Giulio) to dinner. Later, with the Sultan and Bernabo within earshot but out of sight, she appears dressed as a woman and asks Giulio if he knows her. When he repeatedly denies it, she is vindicated, and reunited with her husband.
Boccaccio does not like the tale, and starts another.
Spanish Don Bertrando (Jourdan) is sent to fetch a female doctor, Isabella (Fontaine), for his master, the seriously ill King (Hugh Morton). On the trip, he has to defend her against two highwaymen.
When she is able to cure the King, he offers her anything she wants. She asks for a husband: Bertrando. Dismayed, Bertrando agrees, but immediately after their wedding, he leaves her, as that was all that he had promised to do, and resumes his playboy ways. Before he departs, he tells his new wife that he will only live with her if she obtains the ring on his finger and bears him a child. Determined, she sets out to do just that.
Learning that Bertrando is trying to seduce an innkeeper's daughter Maria (Joan Collins), Isabella has the aggrieved innkeeper send Bertrando a message supposedly from Maria agreeing to spend the night with him. Instead, Isabella keeps the rendezvous in the dark, unlit bedroom. She later steals Bertrando's ring while he is sleeping and leaves before her deception is revealed. Months later, she gives birth to a son. Bertrando shows up, having heard that she claims the child is his. After she tells her story, Bertrando embraces her.
When Fiametta is again critical of Boccaccio's story, he gives up and leaves the villa. However, he returns, takes Fiametta in his arms, and kisses her. She resists at first, then gives in.