- “If you could see your face. Of course, you.”
- — Calypso confessing to Percy Jackson, in The Battle of the Labyrinth
The Battle of the Labyrinth
Percy gets washed up on the island Ogygia. Calypso nurses him back to health. Percy asks her why she pulls away when they're having a good time. Calypso tells him about her curse: she is trapped on this island, and the only people who find it are men that she can't help but fall in love with, but they have another love and are duty-bound to leave. When Percy has to leave, Calypso understands and lets him use a magical raft. Calypso gives Percy a clip of moonlace as a goodbye gift. Percy remarks her as "his biggest what if".
The House of Hades
Calypso seems to still have romantic feelings for Percy. But she was angered that his promise was not made true by the Olympians after the Battle of Manhattan. Gaea offers Calypso to free her from her prison and raise Percy from Tartarus so that she could be with him if she kills Leo Valdez. Unknowingly to Percy, Calypso had cursed his "loved one", Annabeth, with the curse of despair, which was what she felt when Percy left her island. This is shown when both Percy and Annabeth encountered the arai in Tartarus.
The Blood of Olympus
Leo is shown to be angry with Percy for breaking his promise to Calypso. Percy admits to Leo he feels badly about it and doesn't blame her for cursing Annabeth, saying he should've made sure the gods released her and visited her, but lost his memories soon after the Battle of Manhattan and as a result, forgot her.