L'avventura
Anna (Lea Massari) meets her friend Claudia (Monica Vitti) at her father's villa on the outskirts of Rome prior to leaving on a yachting cruise on the Mediterranean. They drive into Rome to Isola Tiberina near the Pons Fabricius to meet up with Anna's boyfriend, Sandro (Gabriele Ferzetti). While Claudia waits downstairs, Anna and Sandro make love in his house. Afterwards Sandro drives the two women to the coast where they join two wealthy couples and set sail south along the coast.
The next morning the yacht reaches the Aeolian Islands north of Sicily. After they pass Basiluzzo, Anna impulsively jumps into the water for a swim, and Sandro jumps in after her. When Anna yells that she's seen a shark, Sandro comes to her side protectively. Later onboard Anna confesses to Claudia that the "whole shark thing was a lie," apparently to get Sandro's attention. After noticing Claudia admiring her blouse, she slips it into Claudia's bag as a gift. At one of the smaller islands, Lisca Bianca, the party comes ashore. Anna and Sandro go off alone and talk about their relationship. Anna is unhappy with his long business trips. Sandro dismisses her complaints and takes a nap on the rocks.
Sometime later Corrado (James Addams) decides to leave the small island, concerned about the weather and rough seas. They hear a boat nearby. Claudia searches for Anna, but she is gone without a trace. Sandro is annoyed, saying this type of behavior is typical. They explore the island and find nothing. Sandro and Corrado decide to continue their search on the island while sending the others off to notify the authorities. Claudia decides to stay as well. Sandro, Corrado, and Claudia continue their search and end up at a shack where they stay the night. As they talk, Sandro takes offense at Claudia's suggestion that Anna's disappearance is somehow due to his neglect.
In the morning Claudia wakes up before the others and watches the sunrise. After finding Anna's blouse in her bag, she meets Sandro out near the cliffs and they talk about Anna, but Sandro now seems attracted to Claudia. The police arrive and conduct a thorough search, but find nothing. Anna's father, a former diplomat, also arrives in a high-speed hydrofoil. When he sees the books his daughter has been reading—Tender Is the Night by F. Scott Fitzgerald, and The Holy Bible—he feels confident that she hasn't committed suicide. The police announce that smugglers were arrested nearby and are being held in Milazzo. Sandro decides to investigate, but before leaving he finds Claudia alone on the yacht and kisses her. Claudia rushes off, startled by his actions. She decides to search the other islands on her own. They all agree to meet up at Corrado's Villa Montaldo in Palermo.
At the Milazzo police station Sandro realizes the smugglers know nothing about Anna's disappearance. When he discovers that Claudia has arrived from the islands, he meets her at the train station where their mutual attraction is evident, but Claudia urges him not to complicate matters and begs him to leave. She boards a train to Palermo, and as the train pulls away, Sandro runs after it and jumps aboard. On the train Claudia is annoyed, saying, "I don't want you with me." She says it would be easier if they sacrifice now and deny their attraction, but Sandro sees no sense in sacrificing anything. Still focused on her friend's disappearance, Claudia is troubled by the thought that it "takes so little to change." Sandro relents and gets off the train at Castroreale.
At Messina Sandro tracks down the journalist, Zuria, who wrote an article about Anna's disappearance. Their meeting is interrupted by crowds of excited men following a beautiful nineteen-year-old "writer" and aspiring actress named Gloria Perkins (Dorothy De Poliolo) who is actually an expensive prostitute. Sandro stops to admire her beauty. Zuria says he heard stories that Anna was spotted by a chemist in Troina. After bribing Zuria to run another story on Anna, Sandro heads to Troina. Meanwhile, Claudia meets up with her boating companions at Corrado's Villa Montaldo in Palermo. No one seems to take Anna's disappearance seriously except Claudia. Even Corrado's young wife Giulia openly flirts with the young prince in front of her husband. After reading Zuria's follow-up story, Claudia leaves the villa for Troina to continue her search.
In Troina Sandro questions the chemist who claimed to have sold tranquilizers to Anna. Claudia arrives and they learn that the woman identified by the chemist left on a bus to Noto in southern Sicily. Sandro and Claudia resume their search together and drive south. Outside Noto they stop at a deserted village, and then find a hill overlooking the town where they make love while a train goes by. Later in town they go to the Trinacria Hotel where they believe Anna is staying. Claudia asks Sandro to go in alone. While Claudia waits outside, a crowd of men gather around her. When she thinks she sees Sandro and Anna coming down the stairs she runs into a paint store, but Sandro follows and confirms that Anna is not there. Claudia remains torn between her feelings for Sandro and her friendship with Anna.
At the Chiesa del Collegio, a nun shows them the view from the roof. Sandro talks about his disappointments with his work, far removed from his youthful ambitions as an architect. Suddenly he asks Claudia to marry him, but she says no—things are too complicated. She accidentally tugs on a rope that rings the church bells, which are answered by connected church bells at another church. Claudia is delighted by the sounds. The next morning she wakes up in a joyful mood, dancing and singing in the room while Sandro looks on amused. They both seem passionately in love. Sandro goes for a walk to the Piazza Municipio, where he notices an ink sketch left by one of the students. With his keychain he "accidentally" knocks over the ink onto the sketch. The student notices and confronts Sandro, who denies he did it on purpose. Sandro returns to the hotel and tries to make love to Claudia, but she resists, telling him they should leave.
At Taormina they check into the San Domenico Palace Hotel where Sandro's employer Ettore and his wife Patrizia are preparing for a party. Claudia decides not to attend because she's tired. At the party Sandro checks out the women—recognizing the beautiful aspiring actress Gloria Perkins. Back in the room Claudia is unable to sleep. Noticing that Sandro has not yet returned, she goes downstairs to Patrizia's room to inquire about Sandro. Claudia confesses that she's afraid Anna has returned and that Sandro will return to her. After searching the hotel, Claudia finally discovers Sandro having sex with Gloria Perkins on a couch. Claudia runs off, and Sandro follows her onto the hotel terrace where he finds her quietly weeping. Sandro sits down on a bench and says nothing; he too begins to cry. Claudia approaches him, and after hesitating, she places her hand on his head in a gesture of compassion and comfort while looking out at the snow-covered image of Mount Etna on the horizon.
mystery