With the help of his father, the wind god Vayu, Hanuman flies through the air to Lanka. He overcomes many obstacles to get there: flying over magical mountains, tricky a serpent goddess, and killing an evil rakshasi.
Finally, he arrives in Lanka. He shrinks to a tiny size to avoid detection and sneaks into the city at night. Lanka is a beautiful place with a high wall and gorgeous gardens, but its people are wicked and corrupt. Hanuman witnesses a number of orgies and other sinful behavior.
He desperately searches for Sita in Ravana's vast palace. He wanders through Ravana's harem, where he sees beautiful women of all races sleeping in their beds. He comes to the bedroom of Ravana himself, but only Ravana and his queen are asleep there. Hanuman is about to give up hope when he catches sight of a white temple in a garden. There is Sita, weeping and surrounded by rakshasis. She is thin and wan from months of being terrorized by Ravana and his people, but she is still more beautiful than any other woman in the world.
As dawn comes, Hanuman watches as Ravana comes out of his palace to confront Sita. He tells her how much he loves her, how rich and powerful he could make her, but she cites her continuing love for Rama and demands once more than Ravana return her to her husband before it is too late. In a rage, Ravana tells her that she has one more month to give into him - then he will kill her and eat her. After Ravana leaves, the rakshasis around her attempt to convince her to give into Ravana: they tell her about his virility and generosity, and the terrible fate that will befall her if she does not accept his love. Despite these torments, Sita remains steadfast in her devotion to Rama.
Hanuman puzzles over how to catch Sita's attention without alarming her or alerting her rakshasi guards. As Sita stands alone under a tree, Hanuman approaches her in the form of a tiny monkey and recites the story of Rama, beginning with his birth in Ayodhya and ending with his alliance with Sugriva, identifying himself as an ally of the king. Hanuman shows Sita the ring of Rama to prove that he is a truthful messenger. Sita is incredulous at first, then delighted to hear news of Rama. Hanuman assures her that Rama is on his way to save her, and offers to bring her back from Lanka himself. Sita refuses, saying that it is dharma for Rama to come slay Ravana and rescue her himself; she adds that she is too chaste to cling to a male other than Rama, which she would have to do if Hanuman brought her across the sea. She gives a piece of her jewelry to Hanuman to show Rama that she is still alive. The two bid each other farewell.
Hanuman decides to cause a little mayhem before heading back to Rama and the vanara army. He changes size to grow extremely tall, and smashes the manicured royal gardens, crying out all along that he is one of Rama's servants. Ravana hears about this and sends out a number of powerful rakshasa warriors to quell Hanuman, but the monkey easily defeats them all. At last Ravana's son Indrajit appears with his magical ropes, and Hanuman allows himself to be captured in order to confront Rama.
When he is taken before the rakshasa king, Hanuman tells him that a great vanara company led by Rama will invade Lanka if Ravana does not release Sita. Ravana might have protection from gods and other supernatural beings, but he never asked for protection from men and monkeys; he will suffer defeat in this conflict.
Ravana is enraged, and orders Hanuman's death. His brother Vibheeshana steps in, saying that it is against dharma to kill a messenger. Ravana relents, and instead decides to light Hanuman's tail on fire and parade him around the city. Hanuman is protected from the pain of his burning tail by the fire god Agni; instead, Hanuman uses this as an opportunity to analyze the layout of the city.
When Hanuman has seen the city, he decides to cause even more mischief. He escapes from his captors and runs through the city, using his burning tail to light buildings on fire. His loving father Vayu fans the flames, causing a conflagration in the city of Lanka. The royal palace and the city burn, but Sita is protected from the flames by her purity.
After roaring Rama's name as a battle cry, Hanuman leaps away from the damaged city, flying back to the shores of India. He tells his companions that he has found Sita, and they head back to the vanara capital of Kishkinda, stopping at the king's vineyards to drink his wine. Though the royal brewers are enraged, Sugriva wisely understands that this means they come with good news. Angada and Hanuman tell Rama, Lakshmana, and the vanara court that they have found Sita in Lanka, offering her golden ornament as proof of this encounter. Rama weeps for joy, and the army begins to plan the invasion of Lanka.
Hanuman's visit to Lanka emphasizes the wickedness of the rakshasa people; Hanuman witnesses a number of sexual indiscretions. This promiscuity contrasts sharply with Rama's behavior around Sita; the wicked Rakshasa is deeply in love with her, and thinks only of her. Still, this does not make him treat her particularly well or grant her what she wants or needs. Instead, he treats her like an object.
Hanuman's rampage in Lanka is a comeuppance for Ravana's cruel acts. Hanuman emphasizes his complete loyalty and devotion to his king Rama; Hanuman attacks the enemy at great cost to himself, all the while identifying himself as Rama's servant and hoping that these acts will benefit Rama.
Even in a moment of apparent humiliation (being paraded around the rakshasa city with his tail on fire), Hanuman finds a way to turn the tables on his captors, lighting their city on fire with his tail. Hanuman accepts capture because he wishes to gather intelligence about the city in order to assist in the vanara invasion.
The victorious search party's consumption of the royal wine is an intriguing episode. Sugriva is wise enough to realize that this means they come with good news; otherwise they wouldn't have pillaged his secret stash of wine. This demonstrates the complexity of Sugriva's character: he is duplicitous enough to kill his own brother, but loyal enough to pledge himself to Rama; he is too obsessed with women and drink to send out a force to assist Rama, but when he finally does, he proves to be an invaluable ally.