For months Summer is trapped in a cellar with the man who took her - and three other girls: Rose, Poppy, and Violet. His perfect, pure flowers. His family. But flowers can't survive long cut off from the sun, and time is running out...

Seven half-bloods shall answer the call To storm or fire, the world must fall An oath to keep with a final breath, And foes bear arms to the Doors of Death *** The House of Hades Holds the Key; To Destroying the World or to Restoring Peace. Percy and Annabeth have been casted into the darkest parts of the Underworld to do the unimaginable. Meanwhile, their friends have to sail to Greece to close the mortal side of The Doors of Death. But the real leader of this quest isn't even part of the Prophecy of Seven... It's Nico di Angelo - the son of Hades.