Okay guys, i just thought I'd put together everything RR told us about The Mark of Athena... It might not be complete. comment if you want to ask or if you have something else...
-third book of the series: Heroes of Olympus.
- the book is coming out Oct. 2, 2012
-there are exactly 580 pages
THE STORY (warning: there may be some spoilers in this article, read on if you dare...)
-Thanatos gives the demigods a clue on where the Doors of Death are.
-Hera warns Percy that Annabeth may cause some trouble
-"wisdom's daughter stands alone, The Mark of Athena burns through Rome"
-"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 link for the thing written on the back of the book (I'm not sure if it's a summary): link
-for the WHOLE first chapter, if you want REAL PAGE FLIPPING ACTION, check out: link
-Riordan said Calypso would make an appearance.
- "THE REAL CLIFFHANGER HASN'T HAPPENED YET"
-The grey streaks in Percy and Annabeth's hair would be mentioned.
Yeah, so guys, that's all I found. Comment if you have something or if you want me to look for something. More info I find will be in the comments... ENJOY!