Ogygia (pronounced oh-jee-jee-ah) is a phantom island that exists everywhere and nowhere. It was designed as the prison for the nymph Calypso, daughter of the Titan Atlas. It is a very gorgeous place, where there are invisible servants and a beautiful garden, made by Calypso herself. One of the garden's plants is moonlace. Its terrain is mostly grass-covered hills with pristine beaches all along the edges, though it has groves of cypress tree. It is apparently not very big as there were few places Leo Valdez could go and not see the ocean.
During Percy's time on Ogygia, Calypso explains that time moves differently on the island. For example, what feels like an hour on Ogygia, could be a week in normal time.
When Percy is leaving he says that he could come back and visit sometime, but Calypso tells him that that "No man has ever found Ogygia twice."
It is thought the inspiration of Ogygia is an actual island in the middle of the Mediterranean Sea called Gozo, the sister island of Malta.
The hero Odysseus was marooned on Calypso's island thousands of years ago for seven years, (although some sources say five, three or even one). He was saved by a plea from Athena to Zeus who sent a message to Calypso by Hermes to release him for his journey to Ithaca or suffer the consequences. Calypso finally, reluctantly, allowed Odysseus to build a small raft, gave him food and wine, and let him depart the island.
Captain Francis Drake was later stranded on the island for a period of time.
Hera sent Percy Jackson to Ogygia to help him heal after he caused Mount Saint Helens to erupt. He was there for awhile before waking up and he was cared for by Calypso. The island seemed like a paradise to Percy, which instantly made him suspicious, as in his experience paradises normally are some kind of trap. However, Calypso soon convinces him that she means him no harm as she plants new flowers in her garden. When he asked how long he had been there, Calypso has problems answering as time moves differently on her island (is it is a phantom island, separated from the outside world).
Percy and Calypso soon grow close to each other, talking about their respective worlds. Percy finds Calypso's island to be beautiful, with its' large gardens that Calypso planted and a good view of the night sky. Calypso, on the other hand, is fascinated by Percy's description of Manhattan, but is saddened by its' lack of gardens and that she could never leave her island, as Ogygia was also her prison. She was never allowed to leave the island since she supported her father during the first war. The gods do visit her from time to time (as one unnamed god visited during Percy's stay on the island), and they tell her about the outside world.
Soon, Hephaestus appeared on the shores of Ogygia, asking Percy if he was going to stay on the island or leave to save his friends, but he would wait until the following morning for an answer. Calypso offered Percy the chance to stay on her island, explaining the full details of her curse, but Percy couldn't stay and decided to go home. Calypso understood that he couldn't stay and offered him a way off the island. Calypso said to Percy "Plant a garden in Manhattan for me, will you?" When he left, he claimed that staying in Ogygia and being with Calypso would always be his biggest what if.
Khione sent Leo Valdez to Ogygia, when she broke into the Argo II with her brothers Zethes and Calais. She thought that with Olympus shut down, there would be no way for Leo to return and get in the way of Gaea's plans. When Leo crashed on Ogygia, he smashed into Calypso's table. Unlike with Percy, Calypso did not treat Leo warmly at first, which annoys Leo, who felt that if Jason Grace had landed there, she'd have wanted him to stay.
When the gods did not answer Leo's prayer to leave, Calypso cursed Zeus, feeling that he is mocking her by sending Leo there. She also cursed Hermes and Hephaestus, possibly for having taken away her earlier guests: Odysseus and Percy respectively. She informed Leo that he is now trapped here, as well. She angrily stormed off, and told Leo that since it was a big island, he should find somewhere far away from her to live. But Leo didn't give up trying to find a way out of there.
During their time together, Leo and Calypso started to grow close, while exchanging witty banter. As Leo tried to build a small boat, Calypso helped him out. She knitted him fire-proof clothes that looked exactly like the clothes he'd worn when he first arrived at Camp Half-Blood. Calypso told Leo about her curse. She explained that he was only the first in a long line of visitors. Leo started to grow angry at Percy for hurting her. Though they both denied it, they began to grow warm toward each other.
After Leo repaired the astrolabe, he saw images of Camp Jupiter's impending attack on Camp Half-Blood. They saw the Kerkopes wreaking havoc for the Romans. Leo and Calypso saw Reyna Avila Ramírez-Arellano on Scipio, making her way toward Greece to meet with the Seven. She had been attacked by gryphons. Upon seeing her, Calypso grew angry, assuming that this was Leo's girlfriend. Leo quickly denied that.
When the raft finally arrived, Calypso realized that Leo couldn't stay behind, and she helped him escape. Leo revealed to her that he planned on returning to her. She told him that that was impossible, that nobody found Ogygia on purpose. As Leo departed, he tried to tell himself that he couldn't be falling in love with an immortal. But as the raft pulled away, Leo vowed on the River Styx that somehow he would return to Ogygia. His meeting with Calypso allowed Leo to forget about Hazel Levesque, who he'd had feelings for before.
After being revived thanks to Festus and the Physician's Cure, Leo manages to return to the island. Leo lands face-first in the sand and reunited with Calypso, who kisses him. Calypso then grabs her bags in preparation for leaving her home with no intentions of coming back and heading to an unknown future with Leo.
List of people sent by the gods to Calypso's island: