The next day, King Alcinous stows Odysseus's many gifts on the ship and everyone feasts. When Odysseus walks onto the ship the next morning, he falls into a deep, sweet sleep – a sleep that resembles death, and that erases briefly the memory of his twenty years away from home. The ship lands in a harbor in Ithaca and the crew places the sleeping Odysseus and his gifts in a spot far away from any road to hide him from thieves.
Like Circe's potion and lotus flower, sleep temporarily erases memory and strips one of will and desire. For Penelope, sleep is a blessing, because she is powerless to take any action. For Odysseus it is often a trap, because he must constantly take action. In this case, though, Athena and the crew protect him from harm, and the sleep seems like a kind of temporary haven from the stress of the last 20 years, almost like a preparation for his return home by making him, for a while, forget that he had ever left.
Poseidon is angered that the Phaeacians helped Odysseus and gave him so much treasure, despite Poseidon's grudge. Zeus considers Poseidon's complaint a bit trivial, but he encourages him to take whatever action will soothe his anger. To take revenge, Poseidon fulfills a prophecy mentioned in book 8: he turns to stone the Phaeacian ship that carried Odysseus to Ithaca just as it returns to the Phaeacian harbor, so that the ship sinks. The Phaeacians are terrified that he will also create a mountain around their harbor and block their access to the sea, as the prophecy says, so they pray and sacrifice to him to try to appease him.
The Phaeacians are following Zeus's code of hospitality in welcoming Odysseus, giving him gifts, and escorting him home. But Poseidon considers their behavior impious: by helping Odysseus, they impede Poseidon's anger, and therefore pit their human wills against his divine will. The situation demonstrates the messy complications of divine justice. Though Zeus might defend the Phaeacians, who obeyed his rules, he chooses not to stand in Poseidon's way.
Back in Ithaca, Odysseus wakes from his long sleep. Athena has surrounded him with mist to protect him, so at first he doesn't recognize his surroundings. He thinks that the Phaeacians tricked him and brought him to some foreign land. Then Athena appears in the guise of a young shepherd, and tells Odysseus that he is in Ithaca, after all. Odysseus conceals his joy and tells Athena (who he doesn't recognize) that he's a fugitive from Crete, wanted for killing a man who tried to steal from him. He says that the Phaeacians took pity on him and brought him to Ithaca while he slept. Now Athena changes into a woman, praises Odysseus for his cunning, and reveals her real identity. She explains that she will help Odysseus hide his treasure and conceal his identity, and warns him that he must suffer further even under his own roof.
Athena's mist is another kind of protective disguise, and ensures that sleeping Odysseus stays out of harm's way. Odysseus follows Agamemnon's advice and keeps his identity hidden from the moment he steps onto home soil. The story he tells Athena is one of many alternate identities he constructs while he's in hiding in his own court. Like many of the stories, the fugitive story is both true and untrue: many of the details are fabricated, but Odysseus did kill the Cyclops for trying to steal his life, and he is a fugitive from Poseidon. This half-truth places emphasis on his guilt.
Odysseus notes that Athena had been kind to him during the war but that she seemed to have abandoned him during his long travels. Athena delights in his grace and cunning: these qualities, she says, are the reason she can't help but stick by him. She explains that she had not helped him during his travels for fear of inciting Poseidon's anger. She tells Odysseus about the suitors' treachery and about Penelope's loyalty. Odysseus realizes he might have died Agamemnon's ignoble death had Athena not warned him, and asks her to help him plan his revenge. She changes Odysseus into an old beggar and tells him to visit his old swineherd, Eumaeus, who remains loyal to him.
Athena's loyalty to Odysseus derives from an odd mixture of justice and affection. Does she protect him because his cunning is honorable and merits reward, or because she finds it charming and impressive (and because she herself is cunning, and therefore admires the trait in others)? We envision the law as cold and objective, but in this world the instruments of the law are emotional and capricious. Similarly, Athena does not protect Odysseus during his journey not because she believes he was wrong or deserving punishment, but because she fears another god.