The Mark of Athena
By Rick RiordanThe Mark of Athena is the third book in the Heroes of Olympus series and is written by Rick Riordan. In this installment of the franchise, The Prophecy of Seven begins as the seven demigods come together on their expedition to the birthplace of the gods. First, they go to Rome to resolve a mysterious quest regarding the Mark of Athena. The first two books in this series established and advanced the plot in these books, but readers could tell that they were mainly trying to develop their respective characters.