The Son of Neptune: The Heroes of Olympus [Book 2]
Rick Riordan
The Heroes of Olympus (2)
The Mark of Athena: The Heroes of Olympus [Book 3]
The Heroes of Olympus (4)
Evil Spy School
Stuart Gibbs
Spy School (3)
The Blood of Olympus: The Heroes of Olympus [Book 5]
The Heroes of Olympus (5)