From The Author

Nico Di Angelo lost his older sister, Bianca, while she was in a mission with his hero, Percy Jackson.
After a while, he meet Hazel a daughter of Pluto, the rome side of his father, Hades. They keep contact, but is not the same.
How will be when he find out that he had another sister? But, she had a "tiny" problem. And that she is in danger, and that she might get herself kill for it...