The Battle of the Labyrinth
Calypso: Because she helped her father Atlas, she is punished by a "house arrest" in an island named Ogygia. The Fates send her a hero that she falls in love with every thousand years or so. After Percy creates an explosion in Mount Saint Helen's, she nurses him back to health. She offers to let him stay forever in Ogygia (he would gain immortality) but he refuses.