The Mark of Athena (Heroes of Olympus Book 3)

An ancient rivalry threatens to shatter a fragile alliance, and the fate of the world hangs in the balance. The seven demigods of the Prophecy have finally united aboard the Argo II, bringing together the long-divided Greek and Roman camps. Their quest takes them to Rome, the ancient heart of power, where they must face giants rising from the earth and confront a force greater than the gods themselves. But their greatest enemy may be the centuries of bad blood between them, a mistrust that Gaea, the Earth Mother, is all too eager to exploit.

For Annabeth Chase, the journey is even more perilous. Haunted by a cryptic gift from her mother, the goddess Athena, she must follow a dangerous solo path known as the Mark of Athena. No child of Athena has ever survived it. To succeed means finding the one thing that could unite the warring camps, but failure will not only ensure their destruction, it will force Annabeth to confront her deepest fears alone. This mission will test the bonds of love, friendship, and loyalty, forcing the heroes to decide if cooperation is even possible when everything is designed to tear them apart.