"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." A terse quatrain casts a teasing challenge at a new combine of demigods in this series launch by Rick Riordan. A tantalizing new adventure epic from the author of Percy Jackson & The Olympians. Bound to be a bestseller (Reader tip: Peruse the first chapter and try to stop. We dare you.)