Two years pass. Guilt over Ptolemy’s death motivates Cleopatra to abandon wine and resume her medical work. When Antonius requests the four Roman legions stationed in Egypt, she dispatches them under Governor Serapion, a man she has long suspected of sympathizing with her exiled sister, Arsinoe.

Faunus brings her news that Serapion has defected, taking the legions to aid Cassius and Brutus. A letter signed by Arsinoe found at his abandoned estate confirms her sister’s involvement. Furious, Cleopatra orders harsh retaliation but withholds additional forces from Antonius.

After Antonius and Octavian triumph at Philippi, a Roman emissary named Dellius arrives to summon Cleopatra to Tarsus for questioning about Serapion’s betrayal. She dismisses him, demanding Antonius come in person. An exchange of increasingly flirtatious letters follows until Charmion urges her to go to Antonius, noting the summons is merely an excuse to see her. Cleopatra finally agrees.

Cleopatra and Charmion travel to Tarsus, leaving Caesarion in Egypt. She sails up the Cydnus River on a spectacular ship with silver oars and purple silk canopies, appearing as a goddess to the crowds. She then repeatedly refuses Antonius’s dinner invitations, making him wait to maintain the upper hand just as Caesar always taught her.

On the fifth day at dawn, Antonius emerges from the river wearing only a loincloth and climbs aboard. She summons her staff for a formal meeting despite his state of undress. In negotiations, she dismisses Serapion as a traitor allied with Arsinoe. When Antonius demands she remain Rome’s ally, she counters by requesting he proclaim Caesarion as Caesar’s heir. He refuses, citing the war it would cause with Octavian, then tells her to ask for anything else.

Cleopatra demands he execute Arsinoe. Antonius agrees immediately. In exchange, she agrees to dine with him. Days later, a white ibis feather falls at her feet, and she knows Arsinoe is dead. Overwhelmed by grief and anger, she screams at the sky for the sister she both loved and was forced to destroy. For their dinner, she dresses as Isis but orders her ship to sail for Egypt instead. When Antonius runs after the ship, she calls back to him that he invited Selene, not Isis. Seeing her divine attire, Antonius laughs.

When a Roman ship approaches Alexandria, Cleopatra fears Octavian has come for Caesarion and prepares for confrontation. The ship belongs to Antonius, who has come alone to claim the dinner she promised. Her lion, Maahes, growls at him as they trade barbed remarks. She agrees but postpones until the Ptolemaia festival in 10 days.

A few days prior, she arranges a garden encounter of flirtatious banter. She jokingly suggests his punishment for a failed compliment should be drowning, so he jumps into a pond and stays under long enough to frighten her. When he surfaces laughing, she pushes him back in.

At the festival, Cleopatra appears in elaborate regalia, riding a chariot driven by Caesarion with Antonius beside them. At the feast that follows, Antonius insists she dance with him, then asks to stay another night. Caesarion interrupts and invites him on their monthly hunting trip.

The next day they go fishing on the Nile and challenge each other to see who can catch the most fish. When Cleopatra notices Antonius’s servant secretly transferring her fish to his bucket, she has Charmion plant a cooked herring in his catch. The trick is exposed and Antonius laughs, conceding that Alexandria is superior to Rome, and asks for a tour the following day.

Cleopatra gives Antonius a tour of Alexandria, including the new harbor, the Caesareum, and the Hospital of Isis. He is impressed by her healing skills and rapport with citizens, and she confesses she always wished to be a scholar rather than a queen. That evening, he reveals a painful shoulder wound from Philippi. She offers to make a poultice but needs willow bark, and Antonius suggests they go to the market in disguise. Despite Charmion’s security concerns, Cleopatra agrees. She changes into plain clothing while Antonius dons a Greek chiton, taking the names Selene and Helios. They slip out through a secret tunnel and row a small boat to the city.

At the marketplace, Antonius buys a small statue of Isis; when Cleopatra is drawn to a carving of Dionysus, he keeps it and gives her the Isis statue. She leads Antonius to the modest home of Apollodorus, the weaver who previously smuggled her into the palace during Theos’s coup. On the boat back, Antonius remarks she is more benevolent than Roman stories claim. She responds that stories are shaped by those who tell them. The tension between them builds until he cups her chin and challenges her to deny her desire. She kisses him, and they make love on the boat.

Cleopatra and Antonius begin their love affair, touring Egypt together and spending the harvest season at the Siwa Oasis. One night, a cobra appears before them. Antonius is frightened, but Cleopatra feels a connection with it, viewing it as both blessing and warning.

Antonius reveals that his wife, Fulvia, and brother, Lucius, have raised an army against Octavian in his name, though he refuses to return to join them. The insurgency fails, and Fulvia dies. Antonius never speaks of it but gets drunk the night they hear the news.

Cleopatra becomes pregnant with twins. While Antonius is out one evening, she discovers a letter from Octavian threatening war if he does not return to Rome. She confronts Antonius and devises a plan: He must return and marry Octavian’s recently widowed sister, Octavia, to forge an alliance. Devastated, Antonius agrees on the condition Cleopatra marry him first according to Egyptian custom.

They wed in the Temple of Isis, dressed as Dionysus and Isis, keeping the marriage private. The next morning, he is gone, leaving behind the small carving of Dionysus. Ten days later, she gives birth to twins, Cleopatra Selene and Alexander Helios. She later receives word that Antonius has married Octavia. That night, she hides her jealousy from Charmion but slips alone into the garden pond, sleeping in her wet clothes and private grief.