User blog comment:SayuriDarling/The Blood of Olympus Official Discussion/@comment-25383342-20141019203132/@comment-7308402-20141020032611

Alright, SPOILERS AHEAD:

When Leo killed Gaea, with the help of Jason, Piper and Festus (and just a little help from Octavian, I should add...) he died. The explosion sent Festus and Leo back to Ogygia, where Festus injected Leo's body with the physician's cure, and he came back to life. He took Calypso out of the island, and they travelled back to civilization, probably to open the Leo and Calypso's Garage!! *happy face*